锅炉与压力容器用钢学习
教材
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绪 论
按国际公约规定，社会经济过程中的全部产品通常分为三类，即硬件产品(hardware)，软件产品(software)，和流程性产品(processed material)。世界各发达国家和我国都把“先进制造技术”列为优先发展的战略性高技术之一。先进制造技术主要指硬件产品的先进制造技术和流程性材料产品的先进制造技术。
工程材料-工程上使用的材料，与工程有关的材料。
一、工程材料发展过程
材料的发展与人类社会的发展紧密联系:
人类社会历史:石器时代、铜器时代和铁器时代
在40-50年代，材料的发展主要围绕着机械制造业，因此，主要发展了以一般力学性能为主的金属材料，
50-60年代，压力容器向高强度方向发展更快，发展了高强度低合金钢。
60年代以后，由于航空、空间机械和动力机械的发展对材料提出了更苛刻的要求。如高温、高压、高的比强度和比模量等。
20世纪后期，材料作为高技术的四大支柱(能源、材料、生命和信息)之一高速发展，新材料特别是非金属人工合成材料如陶瓷材料、高分子材料及复合材料快速发展。
分析
定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析
测试手段如:扫描电镜、电子探针、透射电镜的发展以数字化、计算机的应用加速了材料的发展。 尤其是随着材料的发展，对刀具和模具材料提出了更高的要求，只有陶瓷材料和复合材料的出现，才能更好地满足生产的需要。
工程材料主要应用于机械制造、航空、航天、化工、建筑和交通运输等部门。 石油化工中主要有压力容器，反应器，塔器，换热器，贮槽等。
二、工程材料分类
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
三、材料性能与化学成分和组织结构的关系。
材料的所有性能都是其化学成分和组织结构在一定外界因素(载荷性质、应力状态、工作温度和环境介质)作用下的综合反映。
材料的化学成分和组织结构是其力学性能的内部依据，而力学性能则是具有一定化学成分和组织结构的外部表现。
钢的化学成分是组织结构的主要决定因素之一。
化学成分一定时，可以通过不同的热处理工艺改变材料的组织结构，而导致材料在力学性能上有较大的差异。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
四、选择材料需考虑的因素
在零构件及压力容器设计中，正确地选择结构材料对于保证构件的结构合理、安全使用和降低制造成本是至关重要的。
材料的选择必须要考虑到许多因素，以压力容器为例尽管工艺系统设计人员负责推荐选用于工艺条件的、即具有良好耐腐蚀性能的材料或对介质无污染的材料。但作为设备专业的设计人员，除应了解材料的耐蚀性能外，还必须知道:材料应具有足够的强度和良好的焊接性能和其它加工性能，应选择适合于工艺和机械两方面要求的最经济的材料(这些材料应该是在整个设备工作寿命期限里，考虑到维修、更新等因素在内的成本最低的材料。
选择结构材料时，需考虑的主要因素包括:
(一)使用性能
1( 力学性能
力学性能是针对失效而言。失效三种形式:变形，磨损和断裂。
(1)强度指标——抗拉强度、屈服点;
ζ=P/F
抗拉强度是材料的主要强度指标之一，它是材料在拉伸受力过程中，从开始加载至断裂所能承受的最大应力，是决定材料许用应力的主要依据之一。在GB228“金属拉伸试验方法”中给出了抗拉强度的定义和试验方法。
屈服点是指呈现屈服现象的金属材料，在所加外载荷不再增加(保持恒定)，而材料仍继续伸长变形时所对应的应力(对于在压力容器行业中通常使用的材料，规定以残余伸长率为0(2,时的应力作为决定材料许用应力时的屈服点。GB 228中给出了试验方法。
(2)刚度——弹性模量
刚度是结构抗弯曲和翘曲的能力，是度量构件在弹性范围内受力时变形大小的因素之一，它与材料的弹性模量和结 构元件的截面形状(截面惯性矩)有关。
弹性模量是材料在弹性极限内应力与应变的比值。
GB 150附录1给出了不同类别钢材在不同温度下的弹性模量(
(3)韧性——抗断裂性能;冲击韧性A k
韧性用来衡量材料的抗裂纹扩展能力(对低碳钢、铝、铜一类塑性材料，其晶格结构能够由于裂纹尖端的局部屈服而终止裂纹的扩展;对于类似铸铁等脆性材料，其晶格结构不会使裂纹尖端产生局部屈服现象，不能终止裂纹扩展，因此脆性材料不耐拉伸(而在压缩条件下，任何已经存在的初始裂纹都可能闭合(
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(4)硬度——耐磨性，洛氏硬度，维氏硬度
硬度是抵抗其它物体刻划或压入其表面的能力(用
标准
excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载
试验方法测得的表面硬度是材料耐磨能力的重要指标(如果容器是用于处理有摩擦性的固体或含有可能引起磨蚀的悬浮固体的流体物料时，则应考虑材料的表面硬度(根据试验方法的不同，有不同的量值表示硬度(在压力容器行业中，多采用布氏硬度，其标准试验方法是GB231‘金属布氏硬度试验方皆(其它硬度表示方法及试验方法有:
GB 230 “金属洛氏硬度试验方法”
GB 4340“金属维氏硬度试验方法”
(5)抗疲劳性能——疲劳极限
材料或元件在交变应力(随时间作周期性改变的应力)作用下，经过一段时期后，在内部缺陷或应力集中的部位，局部产生细微的裂纹，裂纹逐渐扩展以致在应力远小于屈服点或强度极限的情况下，突然发生脆性断裂，这种现象称为疲劳，例如频繁进料、出料的周期性间歇操作的设备，应考虑其疲劳失效的可能性(
疲劳极限即材料承受近无限次应力循环(对钢材约为107次)，而不破坏的最大应力值。 对于承受周期性循环载荷的容器分析设计，在即将发布实施以应力分析为基础压力容器设计方法“钢制压力容器 另一标准”中另有专章规定。
(6)抗蠕变性能
蠕变是在一个长时间内，在稳定的拉伸应力作用下材料出现逐渐伸长的现象(对于钢材，通常只有在较高温度下才会发生蠕变;对于少数材料，在中等温度下就有显著的蠕变速度，如铅，甚至在常温下就会在本身重量下产生蠕变。所以用铅作村里时，必须以较小的间隔予以支承固定。GB 150中是以设计温度下经过10万小时蠕变率为1,的蠕变极限作为设计基础的。 (7) 温和低温对力学性能的影响
材料的抗拉强度、屈服点和弹性模量随温度的升高而降低(如果设备的操作温度较高，则必须选用在相应温度下能保持其强度指标的材料。显然，不锈钢比普通碳钢要优越得多。如果材料在高温下承受高的应力，则材料的抗蠕变性能是关键性的(必要时采用特殊合金，如因康镍。
对于0?以下的低温设备，通常的塑性金属材料可能以脆性方式破坏。脆性失效的现象与金属的晶体结构有关。体心立方(bcc)晶格的金属要比面心立方晶格(fcc)的金属更容易发生脆性失效。对于低温容器，如深冷装置和某些液化气体的贮存，有时要规定使用奥氏体不锈钢和铝合金。
引起钢制焊接压力容器脆性破坏的因索非常复杂。它取决于材料的晶格结构，板材的厚度、加工后的残余应力、结构缺陷以及材料的使用温度(
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
目前各国标准规范均以夏比V型缺口冲击试验来检验材料对施性破坏的敏感性，其指标为冲击(吸收)功Akv，即具有一定形状尺寸的金属试样在冲击负荷下折断时所吸收的功，单位为焦耳(J)(标准试验方法有:
GB 2106 “金属夏比(V型缺口)冲击试验方法”
GB 4159 “金属低温夏比冲击试验方法”
所谓材料的使用温度是指容器在正常操作过程中，元件材料可能达到的温度，GB 150规定，该温度不得超过各许用应力表中各钢号所对应的上限温度;对于0?以下的使用温度，要求材料仍能符合对其低温冲击功指标的要求(
2(化学性能
耐腐蚀性能;
3(物理性能
特殊性能:如导热性，硬化性能;
(二)工艺性能
机械加工性能一成型、焊接、锻造、机加工、热处理;
(三)其他
标准系列尺寸一常用板材、管材与型材的规格;
材料价格(
五、压力容器监察机构和设计规范
监察机构:技术监督局
管理规范:锅炉压力容器安全监察条例
设计规范:GB150《钢制压力容器》GB151《钢制管壳式换热器》
六、学习本课程的目的和要求
目的和要求:根据各种实际工作条件选择适当的材料。
七、参考书
1(《锅炉与压力容器用钢》章燕谋著，西安交通大学出版社1996
2(《金属材料及热处理》，史美堂主编，上海科学技术出版社，1980年。 3(《高性能压力容器和压力钢管用钢》陈晓，秦晓钟主编，机械工业出版社，1998年。 4(《金属工艺学》沈锦鳌等主编，航空工业出版社，1991年。
第1章 金属的结晶与合金的构造
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
1.1 金属的晶体构造
1.1.1 晶体概念
指原子(离子)呈
规则
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排列的物体。
晶体特点:
(1)有固定熔点，
(2)原子呈规则排列，宏观断口有一定形态且不光滑
(3)各向异性，由于晶体在不同方向上原子排列的密度不同，所以晶体在不同方向上的性能也不一样。
晶体:绝大多数的固态物质，固态的金属和合金。
非晶体:玻璃，沥青。
1.1.2 金属的晶体结构
晶体有规则的原子排列，主要是由于各原子之间的相互吸引力与排斥力相平衡。 为了便于说明和分析各种晶体的原子排列规律，把原子看成一个点，并用假想的直线将各点连接起来，这样就构成了一个假想的空间格子。这种用以描述原子在晶体中排列的空间格子叫晶格。组成晶格的最基本几何单 元叫晶胞。晶胞各边尺寸及夹角称为“晶格常数”。 1.1.3 三种常见的晶格及分析
(1)体心立方晶格:铬，钒，钨，钼，α-Fe。1/8*8+1=2个原子
(2)面心立方晶格:铝，铜，铅，银，γ-Fe。1/8*8+1/2*6=4个原子
(3)密排六方晶格:镁，锌。6个原子
1.1.3.1 反映金属晶体排列紧密的参数
晶格的致密度:晶胞中所包含的原子所占有的体积与该晶胞体积之比。
配位数:晶格中任一原子周围所紧邻的最近且等距离的原子数。
晶格类型 配位数 致密度
体心立方 8 0.68
面心立方 12 0.74
密排六方 12 0.74
1.1.3.2 晶面与晶向指数:
晶面:晶体中各种方向上的原子面。
晶向:晶体中各种方向上的原子列。
在研究金属晶体结构的细节及其性能时，需要分析它们的各种晶面和晶向中原子分布的特点，因此有必要给各种晶面和晶向定出一定的符号，以表示出它们在晶体中的方位或方向，便于分析。air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
晶面和晶向的这种符号分别叫“晶面指数”和“晶向指数”。
确定晶面指数的步骤:
(1)设晶格中某一原子为原点，通过该点平等于晶胞的三棱边作OX，OY，OZ三坐标轴，以晶格常数a,b,c分别作为相应的三个坐标轴上的量度单位，求出所需确定的晶面在三坐标轴上的截距;
(2)将所得三截距之值变为倒数;
(3)再将这三个倒数按比例化为最小整数，并加上一圆括号，即为晶面指数。晶面指数的一般形式用(hkl)表示。
立方晶格中三个重要晶面100,110,111
晶向指数的确定方法:
(1)通过坐标原点引一直线，使其平行于所求的晶向;
(2)求出该直线上任意一点的三个坐标值;
(3)将三个坐标值按比例化为最小整数，一般用[uvw]表示。
晶面与晶向的原子密度:
晶面原子密度:单位面积中的原子数
晶向原子密度:单位长度上的原子数。
例:体心立方晶格
晶面指数 晶面密度 晶向指数 晶向密度
{100} 1/a2 <100> 1/a
{110} 1.4/a2 <110> 0.7/a
{111} 0.58/a2 <111> 1.16/a
单晶体应用例子:
变压器中的硅钢片晶向指数为<100>，利用了它的磁导率
多晶体结构
如果一个晶体内部的晶格方位完全一致，称为单晶体。工业中实际使用的金属材料，包含了许多小晶体，内部晶格方位一致，但彼此方位不同，多晶体。晶粒与晶粒之间的界面称为晶界。 单晶体各向异性，多晶体一般不显示各向异性。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
1.2 金属的结晶
1.2.1 结晶
液态金属冷却至凝固温度时，金属原子例由无规则运动状态转变为按
一定几何形状作有序排列的状态，这种由液态金属转变为晶体的过程
称为金属的结晶。
冷却曲线:
过冷现象:实际上有较快的冷却速度。
过冷度:理论结晶温度与实际结晶温度之差，过冷度。
1.2.2 结晶过程
不断产生晶核和晶核长大的过程
1.2.3 金属结晶后晶粒大小
一般来说，晶粒越细小，材料的强度和硬度越高，塑性韧性越好。
细化晶粒的方法:
(1) 增大过冷度，增加晶核数量
(2) 加入不熔物质作为人工晶核
(3) 机械振动、超声波振动和电磁振动
1.3 金属的同互异晶转变
大多数金属在结晶完成后的继续冷却中，其晶体结构不再发生变化，如铝、铜等。也有少数金属如铁、钛等。这种金属在固态下晶体结构随温度发生变化的现象称为同素异晶转变。 1538? δ-Fe
1394? γ-Fe
912? α-Fe
因为铁能发生同素异晶转变，在生产中才有可能对钢和铸铁进行各种热处理，改变它的组织与性能，以发挥材料的潜力。
1.4 合金的晶体结构
纯金属一般强度低，工业生产中大量使用的金属材料都是合金，碳钢，合金钢，铸铁，铝镁合金。 1.4.1 合金概念
由两种或两种以上的金属元素与非金属元素组成的具有金属特性的物质称为合金。 1.4.2 合金结构
(1) 固溶体
指溶质的原子溶入溶剂原子的晶格中或取代了栽些溶剂原子的位置，而仍保持溶剂原子晶格类型air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
的一种成分和性能均匀的固态合金。
如铁素体是碳在固溶体中的混合物。
(2) 金属化合物
合金组元间按一定的原子数量之比，相互化合而成的一种具有金属特性的新相，称为金属化合物。如Fe3C(渗碳体)
(3) 机械混合物
由两种或两种以上的相机械地混合在一起而组成的一种多相组织。
如珠光体是渗碳物与铁素体的混合物。
1.5 二元合金状态图的构成
合金状态图即合金结晶过程的简明图解，反映在平衡条件下不同成分合金在不同温度下所存在的相及其相平衡关系，以了解合金在温度变化时的相变过程及组织形成的规律。是分析合金组织、确定热加工工艺、预测材料性能的依据。
1.5.1 二元合金状态图的建立
通过实验建立的
以Pb-Sb合金为例
(1)首先配制几组成分不同的Pb-Sb合金，然后作出它们的冷却曲线
(2)作出每个合金的冷却曲线，并找出各冷却曲线上的临界点(即停歇点和转折点) (3)作一个以温度为纵坐标(单位为?)，以合金成分为横坐标(单位为重量或原子百分数)的直角坐标系统，并自横坐标上各成分点作垂直线——成分垂线，然后把每个合金冷却曲线上的临界点分别标在各合金的成分垂线上。(4) 将各成分垂线上具有相同意义的点连接成线，并根据已知条件分析结果作标记。
相律:合金系在平衡状态下，系统的自由度(f)与组元数(C)和平衡相数(P)之间关系的定律。 f=C-P+2
自由度:保持合金系相的数目不变条件下，可独立改变的影响合金状态的内部及外界因素的数目。 在恒压下，f =C-P+1，对二元系，C=2,则f =3-P，可知: f =0，P=3,平衡相最大为3;P=3，f=0,温度、相成分一定;P=2，f=1,温度或相的成分可变，但只有一个独立变量;P=1;f=2，温度和相成分均可独立改变。
1.5.2 匀晶相图
当两组元在液态和固态均无限互溶时所构成的相图，称为二元匀晶相图。具有这类相图的合金系主要有:Cu-Ni,Cu-Au,Au-Ag,Fe-Ni及W-Mo
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
二元相图的杠杆定律:杠杆定律:用来确定二相平衡时，两平衡相的成分和相对量。 (1)确定两平衡相成分的方法
(2)确定两平衡相相对量的方法:
WL• a r = Wa • r b 或 WL/ Wa= r b/ a r 注意:杠杆定律只适用于两相区。
合金的结晶过程:
匀晶转变:由液相结晶出均一固相过程。
一、相图分析
以Cu-Ni合金相图为例:
相线:液相线、固相线
相区:单相区、两相区
结晶过程:0-1, 1，L相, 降温过程;
1-2，L->α 相变过程;
2，α相，成分为合金成分;
2-3，α相，降温过程;
3，α相，室温组织
相变过程:
t1: 液相开始析出α，α成分由固相线确定,为α1，液相成分L1;
t2: L+α, 成分分别由液相线和固相线确定，为 L2、α2，α1 -> α2， L1 -> L2,两相的相对量用杠杆定律确定; 继续降温，成分分别沿固、液相线变化，W?α ， WL?;
t3:结晶结束，固溶体成分α3=合金成分
总之，结晶过程是一动态过程。
选份结晶(选择结晶):从液相结晶出的固溶体成分与液相成分不同，含有较多的高熔点组元。 固溶体结晶与纯金属结晶的异同:
相同点:一定过冷度，形核与长大过程;
不同点: 纯金属:恒温结晶;结构起伏与能量起伏;结晶时无成分变化;
固溶体:变温结晶;结构起伏、能量起伏和成分起伏;结晶过程总存在原子扩散，以进行溶质在液固两相中的再分配。
1.5.3 二元共晶相图
共晶体:共晶转变所得的两相机械混合物。
当两组元在液态时无限互溶，在固态时有限互溶，而且发生共晶反应时，所构成的相图称为二元共晶相图。如Pb-Sn,Pb-Sb等。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
一、相图分析
相区:3个单相区，3个双相区
相线:液相线，固相线。
共晶反应线，在共晶线上，f=C-P+1=2-3+1=0，在恒温进行，三相的成分恒定。固溶线: MF和NG
点:E点共晶点，共晶反应时液相的成分。
二、典型合金的平衡结晶及其组织
分析要点:临界点、冷却曲线、相状态、成分变化、室温组织与相对量 1.含Sn<19%的合金
2.共晶成分合金(61.9%Sn)
3.亚共晶合金(50%Sn)
4.过共晶合金(80%Sn)
组织与相:不同成分Pb-Sn合金室温下相均为a+b，但组织则因成分而异。Pb-Sn合金组织分区图。
三、初生相和共晶体的组织特征
1. 初生相的组织特征
纯金属或固溶体，一般呈树枝状，平面磨面可呈树枝状、卵形或颗粒状。 亚金属、非金属或金属化合物，一般具有规则外形。
2. 共晶体的组织特征
共晶团:由一个晶核形成的共晶体。
共晶体形态多样:层片状、棒状、球状、针片状、螺旋状等。
3.离异共晶:发生共晶转变时，共晶组织中与先共晶相相同的一相会依附于先共晶相生长，而将另一相推向最后凝固的晶界处，从而失去了共晶组织特征，这种两相分离的共晶体称为离异共晶。 四、共晶合金的不平衡结晶及其组织
1.伪共晶
伪共晶:非共晶成分的合金在快冷条件下得到100%的共晶组织。
伪共晶产生条件:合金过冷至伪共晶区。
2.离异共晶(非平衡条件)
3.其他变化:
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
组织形态:细小
相对量:初生相减少、共晶组织增多
1.5.4 包晶相图
包晶转变:一个液相与一个固相相互作用，生成一个新的固相的转变，即L+β->α 包晶相图:具有包晶转变的相图。Cu-Zn、Cu-Sn、Ag-Pt、Sn-Sb等具有包晶相图。 1.5.5 相图分析方法与应用
一、分析相图的基本方法
• 分析相图中的相和相区
• 分析相图中有无水平直线，并判断其转变类型是共晶型还是包晶型。 • 根据相区接触法则确定图形结构是否合理。相区接触法则即“相邻相区相数差一” • 分析任一合金的结晶过程。
二、利用相图判断合金的性能
1)利用相图判断合金力学性能 (
利用相图可确定合金在某一温度下的相平衡关系，计算各相相对量，再根据各相的性质，大致判断合金性能。
(2)利用相图判断合金工艺性能
第2章 铁碳合金与铁碳合金相图
2.1 铁碳合金的基本组织
1.1. 铁素体
碳与α-Fe中形成的间隙固溶体称为铁素体，用F表示。强度和硬度低，塑性和韧性好。
1.2. 奥氏体
碳与γ-Fe中形成的间隙固溶体称为铁素体，用A表示。高温组织，在大于727?时存在。
塑性好，强度和硬度高于F，在锻造、轧制时常要加热到A，提高塑性，易于加工。
1.3. 渗碳体
铁与碳形成的金属化合物，硬度高，脆性大。用Fe3C
1.4. 珠光体
F与Fe3C混合物。强度，硬度，塑性，韧性介于两者之间。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
1.5. 莱氏体
A与Fe3C混合物硬度高，塑性差。
2.2 铁碳合金状态图
2.2.1 状态图主要点线
主要点
特性点 温度? 含义
A 1538 纯铁熔点
C 1148 共晶点
D 1227 渗碳体熔点
E 1148 C在γ-Fe中最大溶解度
G 912 纯铁的同互异晶转变点
P 727 C在α-Fe中最大溶解度
S 727 共析点
Q 室温 室温时C在α-Fe中最大溶解度
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
主要线:
ABCD线
液相线，液相冷却至此开始析出，加热至此全部转化。 AHJECF线
固相线，液态合金至此线全部结晶为固相，加热至此开始转化 GS线
A3线，A开始析出F的转变线，加热时F全部溶入A ES线
Acm线，C在A中溶解度曲线
ECF线
共晶线，含C量2.11-6.69%至此发生共晶反应，结晶出A与Fe3C混合物，莱氏体。
PSK线
共析线，含C量在0.0218-6.69%至此反生共析反应，产生出珠光体
2.2.2 铁碳合金分类
2.2.2.1 钢 含C量0.0218,2.11%
共析钢 含C量0.77%
亚共析钢0.0218-0.77%
过共析钢0.77-2.11%
2.2.2.2 白口铸铁 2.11-6.69%
共晶白口铸铁 4.3%
亚共晶白口铸铁 2.11-4.3%
过共晶白口铸铁 4.3-6.69% 2.2.3 铁碳合金相图的作用
在铸造方面
选择合适的浇铸温度，流动性好
在煅造方面
选择合适的温度区，奥氏体区
在热处理方面
退火，正火，淬火等
2.2.4 碳对铁碳合金平衡组织和性能的影响
一、含碳量对平衡组织的影响
室温下，铁碳合金均由,+ FeC两相组成 3
随含碳量不同，可分为七个典型组织区
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
二、含碳量对机械性能的影响
• 珠光体P:为F + FeC的混合物，呈层片状，由于FeC的强化作用，珠光体性能较好; 33
• 亚共析钢:由F + P组成，随碳量增加，珠光体量增加，强度性能提高; • 过共析钢:P+ FeC(II)组成，当含碳量,1%， FeC(II)断续分布在晶界处，强度提高;当含33
碳量>1%，FeC(II)呈网状分布在晶界处，强度性能下降。 3
• 莱氏体:硬而脆
第4章 金属材料的变形与再结晶
金属材料在承受外力时，会产生一定的变形，随着外力的增加，其变形将由弹性变形转变为塑性变形，直至断裂。金属材料的变形特性在工程技术上十分重要，
(1)由于铸态金属中往往具有晶粒粗大不均匀、组织不致密及杂质偏析等缺陷，故工业上的金属材料大多要在浇注后经过压力加工再予使用。
(2)把材料制作成所要求的形状。
因为通过压力加工时的塑性变形，金属的组织也会发生很大的变化，可使某些性能如强度等得到显著的提高。但在塑性变形的同时，也会给金属的组织和性能带来某些不利的影响，因此在压力加工之后或在其加工的过程中，还应经常对金属进行加热，使其发生回复与再结晶，以消除不利的影响。
工程上实际材料均为多晶体组织，为了更好地了解多晶体材料的变形，首先了解单晶体的变形特性。
4.1. 单晶体金属变
4.1.1. 单晶体金属弹性变形
单晶体金属材料在正应力作用下变形过程，图(2-1)
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
切应力变形图图(2-2)
特点:
可逆性，去除外力后，变形消失。 (1)
(2) 变形量小，<1%。
(3) 应变与应力成正比。
4.1.2. 单晶体金属塑性变形
单晶体塑性变形有“滑移”和“孪生”等不同方式，大多数情况以滑移方式发生。
正应力只能引起晶格的弹性伸长，或进一步把晶体拉断
切应力可使晶格在发生弹性歪扭之后，进一步造成滑移。通过大量的晶面滑移，最终使试样拉长变细。
滑移:晶体的一部分相对于另一部分沿一定晶面发生相对的滑动。 滑移变形要点:
(1) 滑移只能在切应力的作用下发生
(2) 滑移常沿晶体中原子密度最大的晶面和晶向发生。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
这是因为只有在最密晶面(滑移面)之间的面间距及最密晶向(滑移方向)之间的原子间距才最大，因而原子结合力最弱，所以在最小的切应力下使能引起它们之间的相对滑动。 滑移系:滑移面数与滑移方向数的乘积。滑移系越大，金属滑移的可能性越大，即金属塑性越好。
晶格 体心立方晶格 面心立方晶格 密排六方晶格
滑移面 {110}*6 {111}*4 六方底面*1
滑移方向 {111}*2 {110}*3 底面对角线*3
滑移系 6*2=12 4*3=12 1*3=3
Fe Cu, Al Mg, Zn (3) 滑移时晶体的一部分相对于另一部分沿滑移方向位移的距离为原子间距的整数倍，滑移
的结果会在
晶体的表面
上造成台
阶。
(4) 滑移的同时
必然伴有晶
体的转动，
沿外力方
向。滑移过
程,
4.2. 多晶体金属的变形
4.2.1. 晶界作用
以两个晶粒的试样在拉伸时的变形为例
在远离晶界处，变形明显，在靠近晶界处变形出现“竹节”现象。表明晶界对变形有较大的阻碍作用。
原因:晶界附近晶格排列紊乱，杂质原子往往较多，增大晶格畸变，因而使该处在滑移时位错运动的阻力较大，难以发生变形。
4.2.2. 各晶粒位向差别的影响
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
位向不同当受外力作用时，有些晶粒的滑移面适合于外力作用方向，有些晶粒的滑移面与外力方向相抵触，其中任一晶粒的滑移都必然会受到它周围不同晶格位向晶粒的约束和障碍。所以多晶体金属的塑性变形抗力总是高于单晶体。
4.2.3. 多晶体金属变形过程
滑移面和滑移方向处于或接近于与外力成45度夹角的晶粒必将首先发生滑移变形，不同位向的晶粒分批滑移。
塑性变形特点:
(1) 起始塑性变形的非同时性。
位向不同，所以在工程上无法测得真正的最大弹性变形抗力和真正的起始塑性变形的抗力指标，要采用条件规定的方法
(2) 塑性变形的时间性。
弹性变形以声速进行，变形速度对金属弹性性能无影响，但塑性变形需要时间。缓慢拉伸和快速拉伸。要控制冷变形加工速度。
(3) 塑性变形量的不均一性。
残余应力
(4) 变形过程中伴随着发生金属机械性能及其他物理、化学性能的改变。 形变强化，密度降低，电阻增加，化学活性增大。
4.3. 塑性变形对金属组织和性能的影响
变形后性能的变化是由塑性变形时金属内部组织结构的变化决定的。
4.3.1. 晶粒沿变形方向拉长，性能趋于各向异性
内部晶粒形状与金属外形成比例，变形量大时，产生纤维关“纤维组织” 4.3.2. 晶粒破碎，位错密度增加，产生加工硬化.
形变量不大时，在变形晶粒中的晶界附近出现位错的堆积。随着变形量增大，晶粒破碎为亚晶粒，亚晶界量越多。滑移变形是通过位错在滑移面上移动实现，晶体内部的晶界、亚晶界以及其他缺陷都成为各种阻碍位错移动的障碍物。位错在亚晶界堆积，使滑移变形不易继续进行下去。“晶格畸变”
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
随着形变量增大，由于晶粒破碎和位错密度的啬，金属的塑性变形抗力将迅速增大，即硬度和强度显著升高，塑性和韧性下降，产生“加工硬化”。
4.3.3. 织构现象产生
随着变形发生，各晶粒晶格位向也会沿着变形的方向同时发生转动，故在变形量达到一定的程度(70-90%)时，金属组织将会出现一种织构现象。
织构现象有两种
(1) 各晶粒的某一晶向平行于拉拔方向，丝织构
(2) 各晶粒某一晶面平行于轧制方向，板织构
出现各向异性，不利。
4.3.4. 残余内应力
经过塑性变形，外力对金属所作的功，约90%转化成热，10%转化为内应力残留于金属中。 塑性变形后，退火。
4.4. 塑性变形后的金属在加热时的组织和性能变化
加工硬化会造成进一步加工的困难，退火，一是为了消除加工硬化(再结晶退火)，另一是保留加工硬化，减小内应力。
4.4.1. 回复与再结晶
4.4.1.1. 回复
即在加热温度较低时，仅因金属中的一些点缺陷和位错迁移而所引起的某些晶内的变化。 晶粒大小和形状无明显变化。
冷卷弹簧卷制后低温退火，去应力250,300?。
4.4.1.2. 金属的再结晶
破碎晶粒未改变，组织仍不稳定，加热到较高温度，晶粒外形开始变化，生成新的等轴颗粒。“再结晶”。强度和硬度显著降低，塑性和韧性提高，消除加工硬化。
例:黄铜33%冷轧变形后，在580?再结晶。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
4.4.1.3. 晶粒长大
再结晶完成后，再继续提高加热温度或延长加热时间，晶粒便会继续长大。 因为晶粒长大可降低表面能，热力学第二定律。
4.4.2. 再结晶后的晶粒度
再结晶退火时，要确定加热温度
4.4.2.1. 变形度影响
变形度越大，再结晶温度越低。
因为变形度越大，金属晶体缺陷越多，组织破碎越严重，越不稳定。 变形度增大，再结晶温度降低，并逐渐趋近于一个极限温度，金属的最低再结晶温度。 4.4.2.2. 金属熔化温度的影响
工业纯金属 T=(0.40~0.50)T Rf
T是金属最低再结晶温度，T是金属熔化温度 Rf
4.4.2.3. 金属纯度的影响
有杂质或合金元素时，再结晶温度明显提高。
4.4.2.4. 金属原始组织影响
原始组织的晶粒越粗大，变形阻力越小，晶界少，不容易再结晶，再结晶温度越高。 4.4.3. 再结晶后的晶粒度
影响再结晶后晶粒度的因素
(1) 加热温度和加热时间
再结晶退火时的加热温度越高，晶粒越大。
一定温度，时间越长，晶粒越大
(2) 预先冷变形度
变形均匀度
变形越大，变形越均匀，再结晶后晶粒度越小。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
第5章 金属材料的脆性 5.1. 金属材料的断裂
金属在外加载荷的作用下，当应力达到材料的断裂强度时，发生断裂。 断裂是裂纹发生和发展的过程。(图)
5.1.1. 断裂的类型
根据断裂前金属材料产生塑性变形量的大小，可分为韧性断裂和脆性断裂。 韧性断裂:断裂前产生较大的塑性变形，断口呈暗灰色的纤维状。
脆性断裂:断裂前没有明显的塑性变形，断口平齐，呈光亮的结晶状。 韧性断裂与脆性断裂过程的显著区别是裂纹扩散的情况不同。
图5-1 韧性断裂和脆性断裂时裂纹扩展的比较 韧性断裂和脆性断裂只是相对的概念，在实际载荷下，不同的材料都有可能发生脆性断裂;同一种材料又由于温度、
应力、环境等条件的不同，会出现不同的断裂。
5.1.2. 断裂的方式
根据断裂面的取向可分为正断和切断。
正断:断口的宏观断裂面与最大正应力方向垂直，一般为脆断，也可能韧断。 切断:断口的宏观断裂面与最大正应力方向呈45?，为韧断
5.1.3. 断裂的形式
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
裂纹扩散的途径可分为穿晶断裂和晶间断裂。
穿晶断裂:裂纹穿过晶粒内部，韧断也可为脆断。
晶间断裂:裂纹穿越晶粒本身，脆断。
5.1.4. 断口分析
断口分析是金属材料断裂失效分析的重要方法。记录了断裂产生原因，扩散的途径，扩散过程及影响裂纹扩散的各
内外因素。所以通过断口分析可以找出断裂的原因及其影响因素，为改进构件设计、提高材料性能、改善制作工艺
提供依据。
断口分析可分为宏观断口分析和微观断口分析。
5.1.4.1. 宏观断口分析
断口三要素:纤维区，放射区，剪切唇。
纤维区:呈暗灰色，无金属光泽，表面粗糙，呈纤维状，位于断口中心，是裂纹源。 放射区:宏观特征是表面呈结晶状，有金属光泽，并具有放射状纹路，纹路的放射方向与裂纹扩散方向平行，而且这些纹路逆指向裂源。
剪切唇:宏观特征是表面光滑，断面与外力呈45?，位于试样断口的边缘部位。 5.1.4.2. 微观断口分析
自学
5.2. 脆性破坏事故分析
脆性断裂有以下特征:
(1) 脆断都是属于低应力破坏，其破坏应力往往远低于材料的屈服极限。 (2) 一般都发生在较低的温度，通常发生脆断时的材料的温度均在室温以下20?。 (3) 脆断发生前，无预兆，开裂速度快，为音速的1/3。
(4) 发生脆断的裂纹源是构件中的应力集中处。
防止脆断的措施
(1) 选用低温冲击韧性好的钢材。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(2) 尽量避免构件中应力集中
(3) 注意使用温度。
5.3. 韧-脆性转变温度
为了确定材料的脆性转变温度，进行了大量的试验研究工作。如果把一组有缺口的金属材料试样，在整个温度区间中的各个温度下进行冲击试验。
低碳钢典型的韧-脆性转变温度。随着温度的降低，材料
的冲击值下降，同时在断裂面上的结晶状断面部分增加，
亦即材料的韧性降低，脆性增加。
有几种方法
(1) 冲击值降低至正常冲击值的50,60%
(2) 冲击值降至某一特定的、所允许的最低冲击值时
的温度。
(3) 以产生最大与最小冲击值平均时的相应温度
(4) 断口中结晶状断面占面积50%时的温度
2对于厚度在40mm以下的船用软钢板，夏比V型缺口冲击能量为25.51J/cm时的温度作为该材料的脆性转变温度。
5.4. 无塑性温度
韧-脆性转变温度是针对低碳钢和低碳锰钢，其它钢材，无法进行大量试验。 依靠其它试验方法，定出该材料的“无塑性温度”NDT
(1) 爆炸鼓胀试验
正方的试样板上堆上一小段脆性焊道，在焊道上锯一缺口。在试样上方爆炸，根据试样破坏情况判断是否塑性破坏。
平裂，凹裂，鼓胀撕裂
(2) 落锤试验
5.5. 金属材料产生脆性断裂的条件
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
5.5.1. 温度
任何一种断裂都具有两个强度指标，屈服强度和表征裂纹失稳扩散的临界断裂强度。 温度高，原子运动热能大，位错源释放出位错，移动吸收能量;温度低反之。
5.5.2. 缺陷
5.5.2.1. 材料韧性
裂纹尖端应力大，韧性好发生屈服，产生塑性变形，限制裂纹进一步扩散。
5.5.2.2. 裂纹长度
裂纹越长，越容易发生脆性断裂。
5.5.2.3. 缺陷尖锐程度
越尖锐，越容易发生脆性断裂。
5.5.3. 厚度
钢板越厚，冲击韧性越低，韧-脆性转变温度越高。
原因:
(1)越厚，在厚度方向的收缩变形所受到的约束作用越大，使约束应力增加，
在钢板厚度范围内形成平面应变状态。
(2) 冶金效应，厚板中晶粒较粗大，内部产生的偏析较多。 5.5.4. 加载速度
低强度钢，速度越快，韧-脆性转变温度降低。
5.6. 金属材料的脆化现象
分两类:
(1) 在一定温度条件下出现的脆性，温度条件改变后，脆性自行消失，或者在一定温度条件下，经一定时间后出
现的脆性。
这种情况下，金属的组织变化不明显。有冷脆性，热脆性，红脆性及回火脆性。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(2)由于应力的反复作用，介质的浸蚀以在高温下长期工作后，金属组织改变引起的脆化现象。这种脆性无法消除
或要通过一定的特殊方法消除。如苛性脆化，氢脆，热疲劳，石墨化。 5.6.1. 冷脆性
冷脆性:金属材料在低温下呈现的冲击值明显降低的现象。
影响因素:化学成分
(1) 含碳量
(2) 锰
(3) 镍
(4) 磷
5.6.2. 热脆性
热脆性:某些钢材长时间停留在400,500?温度区间再冷却至室温，其冲击值有明显下降。 影响因素:
(1) 化学成分
含C量，铬锰钼磷等
(2) 保温时间
不同钢产生热脆性所需的保温时间不同
(3) 热处理
调质处理可阻止热脆性产生。
5.6.3. 红脆性
含S较多的钢中，在800,900?以上呈现较大脆性。S化物以网关分布在晶界上。 消除方法:
(1) 长时间高温退火，使网状S化物变为球状。
(2) 加入锰，硫化锰以点状，球状存在于晶界上。
5.6.4. 回火脆性
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
对于一般钢回火可提高冲击韧性。
但某些钢在回火后，冲击韧性反而降低。回火脆性。
5.6.4.1. 第一类回火脆性
发生在合金结构钢中。但某些钢在250,400?回火后，冲击韧性反而降低。实际遇到机会少。 5.6.4.2. 第二类回火脆性
在450,600?长时间回火或在更高温度(600,700?)回火后，出现常温冲击韧性下降。 再次回火消除
或加入钼钨防止。
对于一般钢回火可提高冲击韧性。
5.6.5. 苛性脆化
苛性脆化:金属材料的局部高应力区与具有一定浓度的氢氧化钠溶液相接触而发生的电化学晶间腐蚀脆化现象称为苛性脆化。
材料在高应力作用下，晶粒本体与晶界产生电位差，当与具有一定浓度的氢氧化钢溶液相接触，晶界部位的铁离子将进入溶液中，与溶液中的氢氧根离子发生电化学反应。
如果溶液中的氢氧化钠浓度较高，溶液中的氢氧根负离子较多，促使晶界部位的铁离子大量进入溶液，发生电化学反应，从而形成晶间裂纹，导致苛性脆化。
材料产生苛性脆化必须具备三个条件:
(1) 在材料中需存在较高的局部应力，对于碳素钢高达250MPa ;
(2) 需具有较高浓度的氢氧化钢溶液与材料的局部高应力区相接触，并且在溶液中需具有能加速反应的催化剂; (3) 需具有一定温度。
在锅炉的铆接或胀接部位最易发生苛性脆化。
应力: 工作应力+联接应力+附加应力
化学成分:铆接或胀接处锅水渗漏，浓缩
温度:低压锅炉为200?，中压锅炉为250?，高压锅炉为300?
5.6.6. 氢脆
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
金属在外加载荷的作用下，当应力达到断裂强度时，发生断裂。
第6章 金属材料的高温机械性能 高温下承载材料的机械性能与室温承载材料有很大区别:比如
(1) 强度降低，在不同温度下进行金属材料的静拉伸试验时，可以发现，随着试验温度的升高，屈服平台消
失，而且材料所能承受的最大载荷也降低。图
(2) 塑性增大。
在高温条件下，影响材料机械性能的因素增多，不仅温度有影响，应变速度，断裂所需时间也有影响。
6.1. 金属材料的蠕变形象
6.1.1. 蠕变现象
蠕变:金属材料在长时间的恒温、恒应力作用下，发生缓
慢的塑性变形。
碳素钢超过300,350?，合金钢超过400,450?发生
蠕变曲线:三个阶段
oa开始部分，加载引起的瞬时变形
ab第1阶段，速度大，不稳定阶段，减速阶段，η1，ε
1
bc第2阶段，稳定阶段，等速阶段η2，ε2
cd第3阶段，最后阶段，加速阶段η3，ε3，不能计入元件寿命期。 6.1.2. 蠕变曲线的表示方式
数学模型，主要表示第一阶段和第二阶段
蠕变条件下蠕变速度随时间变化可用下式来表示
其中A，n为外界条件与材料性质的常数 第一阶段两种式子
第二阶段
6.1.3. 金属材料在蠕变中的组织变化
6.1.3.1. 滑移
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
整个蠕变过程中，有滑移产生
6.1.3.2. 亚晶形成
晶粒变形不均匀破裂，形成亚晶
6.1.3.3. 晶界形变
晶界也参与形变，有时高达40-50%
6.1.4. 金属材料的蠕变理论
蠕变是在一定的温度和应力作用下发生的，与原子热运动有关。原子热运动作用大致有两方面:
(1) 是在应力作用下原子直接大量地定向扩散
(2) 协助受阻位错克服障碍重新运动
一方面形变硬化，一方面回复
6.1.5. 金属材料的蠕变断裂机理
金属材料蠕变断裂分2种:晶间和穿晶
穿晶:有大量塑性变形，韧性，高应力，低温
晶间:塑性变形小，脆性，低应力，高温
等强度温度概念
两种理论:楔形蠕变裂纹(三晶交界处应力集中，穿晶)，空洞形(空洞在三晶交界处汇集，晶间)
6.2. 金属材料的高温强度
6.2.1. 条件蠕变极限
根据不同的需要有2种
(1) 给定温度下，引起规定变形速度的应力值
(2) 一定工作温度下，在规定时间内，使试件发生一定量总变形时的应力值 6.2.2. 高温持久强度
在给定温度下，经过一定时间而断裂时所能承受的最大应力。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
表示材料在温度t经过η而断裂时所能承受的最大应力
与蠕变区别:蠕变考虑变形为主，高温持久强度主要考虑材料在长期使用下的破坏抗力。 6.3. 蠕变和持久强度的推测方法
必须进行长期试验，应用外推方法，可大大缩短时间。
外推法:(1)总结金属材料试验数据，找出经验关联式，用以外推 (2)从微观出发，建立应力，温度和断裂时间的关系式。
等温线法:在同一试验温度下，用较高温度应力进行短期试验数据。(加大强度) 6.4. 钢的持久塑性
是高温条件下工作的重要指标之一。
细小碳化物(Mo2C，VC)在晶内析出，提高晶内强度，削弱晶界强度，形成低塑性的晶间断裂。
影响因素
(1) 合金元素
加入硼强化晶界，减小有害元素S等
(2) 金相组织
珠光体-F>贝氏体>马氏体
(3) 热处理
奥氏体化温度d，回火温度a
6.5. 影响材料高温强度性能的因素
提高材料高温强度关键
(1) 使在蠕变变形过程中受到阻碍而堆积的位错不容易重新开始运动 (2) 大力强化晶界，避免晶间开裂
6.5.1. 化学成分
6.5.1.1. C
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
<0.4%高温强度随碳增加而增加
不同钢种有最佳值。
6.5.1.2. 其它合金元素影响
Mo可提高材料高温强度
V,Nb,Ti可强烈形成碳化物，在钢中形成弥散分布的沉淀相，有良好强化效果。 P强化晶界
(1) 每种合金元素的作用与其质量分数不成正比，往往有一最佳值。 (2) 每种合金元素的质量分数越高，则单位质量分数所引起的作用越小。因而多元素，少质量分数的钢种有良好
的高温性能
6.5.2. 冶炼方法
钢中气体量，晶界处的偏析，夹渣对钢高温性能影响大。 减小有害元素，选择适当的冶炼方法
6.5.3. 金属材料的组织结构
6.5.3.1. 碳化物形状分布
片状弥散分布热强性好，球状聚集不好
6.5.3.2. 晶粒度
常温下， 细晶粒具有高强度
高温下细晶则易蠕变， 此时有个最佳值
6.5.4. 热处理方法
热处理后，在常温下使用，不发生组织变化，可行
而在高温下，不稳定的结构组织将发生变化，使高温性能变坏。 6.5.5. 温度波动对钢材高温强度的影响
温度对钢和的高温强度影响，主要有2方面
(1) 温度的波动使实际温度高于规定温度
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(2) 附加热应力
6.6. 金属材料的松驰
6.6.1. 金属材料的松驰特性
松驰:金属材料在高温和应力状态下，如果维持总变形量不变，随着时间的延长，应力逐渐降低的现象。
如果总变形量不变，弹性变形转变为塑性变形
应力松驰分2阶段，
第1阶段应力随时间急剧降低，第2阶段应力下降缓慢并趋向恒定。恒定值为松驰极限。因为松驰极限小，通常不用它来评定材料的抗松驰能力，而用一定时间内，材料中应力的降低值 来表征材料抗松驰性能。
松驰稳定系数S0，不考虑初应力，更合理。a
6.6.2. 松驰的塑性应变速度
低碳钢只与应力有关
合金钢在第1阶段与应力和总应变有关，第2阶段，只与应力有关。 6.6.3. 再紧固对松驰的影响
在动力装置上，常采用法兰螺栓联接，为了保证联接的紧密性，使用一定时间后要再次紧固。 单纯松驰与再紧固松驰见下图:
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
6.6.4. 应力松驰与蠕变的关系
松驰与蠕变有差别也有联系
差别:蠕变是恒定应力下，塑性变形随时间的延长而不断增加的过程;松驰是恒定变形下，应力随时间的延长不断
降低过程，此时塑性变形的增加是与弹性变形的减小等量同时发生。
联系:本质相同，松驰也可看作是应力不断降低时的多级蠕变。
第7章 长期在高温条件下金属材料组织结构变化
在室温条件下，钢材的组织比较稳定，不随时间而改变。在高温下，由于金属原子热运动，在长期工作中，金相组织会将不断发生变化，并可能导致性能改变。
钢材长期在高温条件下的组织变化主要有:珠光体球化，石墨化，合金元素重新分配。 7.1 珠光体球化
锅炉及压力容器上常用的碳素钢及低合金钢都是过共 析珠光体钢。
P中F和FeC均呈薄片状分布。 3
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
片状物的表面积与体积之比球状物的表面积与体积之比大，即在同样体积情况下，片状物比球状物有更大的体积。因此，片状物比球状物具有更大的表面能。根据热力学第二定律，具有较大能量的状态有自行向能量较小的状态转变的趋势。所以片状珠光体是一种不稳定的组织，其中渗碳体有自行转变成球状并聚集成大球团的趋势。这种球化过程是以扩散为基础的，当温度较高时，原子的活动能力增强，扩散速度加快，
片状渗碳体逐渐转变成球状，再聚集
成大球团。
球化-聚集见右图
7.1.1 球化对金属性能的影响
7.1.1.1 对室温机械性能影响
降低室温强度σσ 及sb
对低碳钢和低碳钼钢:
中等程度球化，强度指标下降10-15%
严重球化，强度指标下降20-30%
7.1.1.2 对高温机械性能影响
蠕变极限和持久强度下降
表 严重球化对0.5Mo钢高温强度的影响
试验温度(?) 482 538
蠕变极限降低的百分数(%) 46 23
持久强度降低的百分数(%) 52 45 7.1.2 影响珠光体球化的因素
影响球化过程发展的主要因素是温度，时间和化学成分
珠光体球化和碳化物聚集是基于扩散的一种过程，温度对球化过程必然有很大影响。 公式
T-绝对温度，A-物性参数，b-常数，e-自然对数底
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
温度升高，完全球化所需的时间便明显减少。
碳扩散速度与合金元素对碳在固溶体中扩散的影响有关。因而，凡是能形成稳定碳化物的合金元素，或进入固溶体中可降低其原子扩散系数的合金元素，均能阻止或减缓球化及其积聚过程。单纯碳钢最易球化，钛 、铌、钼、铬、钒可提高球光体稳定性。
此外，在钢的化学成分的温度相同的条件下，球化速度还与钢的晶粒度，冷加工变形度和渗碳体片大小有关。
细晶粒钢，球化时间短，总表面积大
冷加工变形度大时间短，塑性变形中的晶格畸变，导致内能增加，扩散速度加快，球化过程首先在此发生。
过小的渗碳体片缩短了扩散距离，加速球化。
7.1.3 珠光体球化的级别
分6级
未球化 第1级
倾向性球化 第2级
轻度球化 第3级
中度球化 第4级
完全球化 第5级
严重球化 第6级
7.1.4 材料发生球化后的恢复处理
可采用热处理恢复
4例:16Mo钢的θ245×26蒸汽管道在9.8Mpa，510?条件下运行约8*10h后，珠光体球化，碳化物聚集在晶界上，67%Mo进入碳化相中，机械性能恶化。
加热至920?，停留1h，在炉中打开炉门冷却80-90?/h。
7.2 石墨化
钢中渗碳体在高温长期作用下自行分解的一种现象。
FeC——>3Fe+C 3
石墨开始以细微点状出现，逐渐聚集成越来越粗的颗粒，石墨强度低，相当于在金属内部产生空穴。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
7.2.1 对材料影响:
脆性急剧增大。
7.2.2 影响石墨化因素
温度 :
高温下，是一个扩散过程
合金元素 :
与碳结合能力强的元素均可阻止石墨化发生铬，钛，钒 ;促进石墨化，硅，铝，镍 晶粒大小:
细晶粒钢及有加工硬化钢易发生。
7.2.3 石墨化分级
1级 不明显
2级 明显
3级 严重
4级 很严重
7.3 合金元素在固溶体和碳化物之间的重新分配
在高温下使合金元素原子活动能力增加，对一些起固溶强化作用的合金元素，铬，锰，钼(固溶体)脱落，转移至碳化物中。
固溶体引起晶格畸变从而起到强化作用，畸变晶格不稳定，在高温下就有向较稳定的碳化物中转移的趋势。
(固溶体和碳化物中)合金元素成分的变化及对高温机械性能影响:
常用珠光体热强钢 :(1)铬钼低合金钢(2)铬钼钒低合金钢
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
第8章 钢的过热与过烧
8.1 概述
在锅炉和压力容器制造中，对所用钢材进行热加工和热处理。此时，如果加热温度控制不当，加热不均会使材料超温，导致材料机械性能恶化。
根据超温的程度和时间长短，钢材会发生脱碳，过热和过烧现象。
过热:钢被加热到Ac3以上某一温度，随着奥氏体晶粒的长大，在粗大的奥氏体晶界上，发生了化学成分的明显变化(主要是硫的偏析)，在冷却时，或者在原始奥氏体晶界上保持了硫的偏析，或者产生了第二相(主要是硫化物)质点的网状沉积，导致晶界脆化，使钢的拉伸塑性和冲击韧性明显降低的现象。
开始发生过热现象的温度为过热温度。不稳定过热(可恢复)，稳定过热
如果没有硫的析出，不算是过热。
过烧:钢被加热到接近固相线或固-液两相温度范围内的某一温度后，在十分粗大奥氏体晶界上不仅发生了化学成分的明显变化(主要是硫和磷的偏析)，而且局部或整个晶界出现烧熔现象，从而在晶界上形成了富硫，磷的液相。在随后的冷却过程中，晶界上产生富硫，磷的烧熔层，并伴随着形成硫化物，磷化铁等脆性相的沉积，导致晶界严
重弱化，从而剧烈降低钢的拉伸塑性和冲击韧性的现象。
开始发生过烧现象的温度为过烧温度。
8.2 钢在高温加热中的变化
8.2.1 奥氏体晶粒长大
8.2.1.1 奥氏体晶粒长大速率
D-晶粒长大后的平均晶粒直径，K-物性参数，t时间。 8.2.1.2 奥氏体晶粒长大影响因素
8.2.1.2.1 化学成分和冶炼方法
本质晶粒度指钢被加热到Ac3以上某一温度时奥氏体晶粒的大小。
本质粗晶粒钢在冶炼时只用锰铁脱氧(沸腾钢)或用锰铁、硅铁脱氧的钢
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
本质细晶粒钢指在除锰铁和硅铁脱氧外，还用铝作脱氧剂的钢。 8.2.1.2.2 碳及合金元素
含碳量增加，晶粒长大倾向增大。
强烈抑制晶粒长大:Al,Ti,Nb,V,Zr
中等抑制晶粒长大:Mo,W,Cr
微弱抑制晶粒长大:Cu,Co
增加晶粒长大倾向:Mn,P
8.2.1.2.3 加热温度
8.2.1.2.4 保温时间
8.2.2 钢在高温加热时的成分和组织变化
8.2.2.1 第一阶段
钢从Ac3温度到其过热温度以下的温度区间内加热。奥氏体逐渐长大。 8.2.2.2 第二阶段
过热温度到过烧温度
硫析出
8.2.2.3 第三阶段
指从钢的过烧温度至固-液相线温度区间内加热。
在晶界上形成富硫，磷液相
8.3 高温加热后的冷却
8.3.1 第一阶段加热后的冷却
在此阶段加热后冷却，当冷至Ar3温度，A析出F，至Ar1，奥氏体发生共析反应转变为P。
如在Ar3至Ar1冷却较快，会析出F的魏氏体组织。降低钢的冲击性能，会使钢的机械性能恶化。
8.3.2 第二阶段加热后的冷却
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
硫在铁中的溶解度很低，且随着温度的降低而急剧减少。 第二阶段加热后冷却，冷却速度越高，冷却后的钢越接近于高温下的平衡状态;反之，晶界上的硫以平衡偏析为主，
且在冷却过程中析出的硫化锰质点，将在缓慢冷却过程中逐渐聚集成团。 8.3.3 第三阶段加热后的冷却
粗大的A晶界上有富硫，磷的液相出现，特别是磷在晶界上的严重偏析。 8.4 钢的过热
8.4.1 钢的过热温度
1200,1350?之间。
8.4.2 过热钢的特征
8.4.2.1 宏观断口
不稳定过热:结晶状断面
稳定过热:无金属光泽的灰白色粒状断面
8.4.2.2 显微特征
粗大的A晶粒，魏氏体组织，原始A晶界处S偏析或硫化锰沉淀 8.4.3 过热钢的机械性能
塑性和冲击韧性明显降低，对强度和硬度基本无影响
8.4.4 钢发生过热后的补救措施
正火，淬火和回火
8.5 钢的过烧现象
8.5.1 钢的过烧温度
通常比过热温度高几十至一百度左右
8.5.2 过烧钢特征
8.5.2.1 宏观断口
无金属光泽的灰白色石状断面
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
8.5.2.2 显微特征
粗大的A晶粒，魏氏体组织，原始A晶界处富P，S烧熔层及原始奥氏体晶界上硫化锰和磷化铁沉淀。
8.5.3 过烧钢的机械性能
塑性和冲击韧性严重降低，必须报废。
第9章 金属材料的腐蚀
9.1 概述
金属腐蚀是指金属与其周围介质发生化学或电化学腐蚀而产生的破坏现象。 锅炉与压力容器的一些主要承压元件在使用过程中与一些腐蚀介质接触，会发生各种腐蚀现象，引发破裂损坏事故，后果
(1) 往往引发事故造成巨大经济损失
(2) 耗费大量资源和能源，1/3冶炼金属由于腐蚀而破坏
(3) 污染环境
因此有必要对腐蚀现象进行研究。
9.1.1 分类按机理
9.1.1.1 化学腐蚀:金属与非电解质介质直接发生纯化学反应。服从于多相反应的化学动力学的基本规律。例如:金属在高温下发生的氧化现象。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
9.1.1.2 电化学腐蚀:金属与电解质溶液发生电化学作用而引起的破坏现象，构成了原电池，
服从于电化学动力学规律。
电化学腐蚀是金属腐蚀的更重要更普遍的形式。
9.1.2 按腐蚀环境分类
大气腐蚀，土壤腐蚀，高温气体腐蚀，海水腐蚀等。
9.1.3 按腐蚀的形式:
9.1.3.1 均匀腐蚀
腐蚀作用以基本相同的速度在整个金属表面同时进行。危害性小，可估计腐蚀速度。 例:碳钢在强酸中的腐蚀
9.1.3.2 局部腐蚀
发生在金属的局部地区。
9.1.3.2.1 应力腐蚀裂开
材料在静拉伸应力与腐蚀介质作用下发生的破坏现象。主要是晶间，脆断。也有穿晶。在氮化物，碱性氮氧化物或其它水溶性介质中常有发生。
9.1.3.2.2 点蚀
发生在金属表面局部区域，点蚀形成后迅速向深处发展，最后穿透金属。出现后就及时磨光或涂漆，避免进一步深入。不锈钢，铝及其合金，钛及其合金在氯离子介质中易发生。 9.1.3.2.3 晶间腐蚀
在金属材料晶界部位的腐蚀。腐蚀沿晶间进行，使晶粒之间的结合力大大削弱，机械强度急剧降低。不锈钢，铝镁合金。
9.1.3.2.4 缝隙腐蚀
金属与金属或金属与非金属之间存在细小缝隙中发生的腐蚀现象。法兰联接面，螺母压紧面。 9.1.3.2.5 电偶腐蚀
电解质溶液中，不同的金属接触时，由于腐蚀电位差引起电位低的金属在接触部位腐蚀的现象。如碳钢与黄铜在海水中接触。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
9.1.3.2.6 腐蚀疲劳
金属在交变应力和腐蚀介质的作用下发生。产生腐蚀坑和大量裂纹，显著降低钢的疲劳强度。 9.1.4 腐蚀共同特性
9.1.4.1 从热力学角度看，腐蚀是金属由非稳态自发向稳态的一个转变过程。 9.1.4.2 是化学，电化学过程。
9.1.4.3 总是发生在表面，从表面开始。
9.2 金属材料的高温氧化
9.2.1 高温氧化过程的机理
氧与氧化性气体介质的化学反应。
发生氧化反应判据
(1) 初始系统(金属和氧)的等压-等温自由能与最终状态时的差值。 (2) 系统中氧的分压高于金属氧化物的分解压力。 氧化过程2个阶段
(1) 化学反应过程，氧与表面金属接触反应，形成氧化膜
(2) 电化学反应，内部金属腐蚀，分7步骤
1) 氧分子吸附至氧化膜
2) 氧分子分解为氧原子
3) 氧原子形成离子
4) 氧化膜中的阴离子向金属表面迁移
5) 金属原子电离及阳离子向氧化膜过渡;
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
6) 氧化膜中的阳离子和电子向膜气相界面迁移;
7) 阳离子和阴离子作用并产生金属氧化物 氧化膜的保护性能
(1) 氧化膜能完整性，指完整地覆盖在基体金属表面 (2) 氧化膜的强度，塑性及与基体金属结合力 (3) 高温下的稳定性。
9.2.2 高温氧化过程的动力学规律
常见的直线，抛物线，对数规律
9.2.2.1 直线规律
氧化物不多孔性氧化膜时,
镁在450?以上，钼在550?以上。
9.2.2.2 抛物线规律
金属表面附一层致密氧化膜，
氧化开始时候为最大氧化速度，此后不断减小，趋近于0
镍和铜大于500?，铁在大于700?
9.2.2.3 对数规律
低温，动力学规律
氧化开始时候为最大氧化速度，此后很快减小，趋近于0 9.2.3 氧化的温度规律
低温为对数规律，中温为抛物线，高温为直线规律 9.2.4 金属材料的高温抗氧化性指标
9.2.4.1 金属重量变化指标
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
9.2.4.2 腐蚀深度:
应用较多。
钢材耐热性级别
级别 腐蚀深度(mm/a) 耐热性分类
1 <=0.1 完全抗氧化性
2 >0.1,1.0 抗氧化性
3 >1.0,3.0 次抗氧化性
4 >3.0,10.0 弱抗氧化性
5 >10.0 不抗氧化性 锅炉高温承压元件，只允许用1级
9.3 金属材料的电化学腐蚀
金属材料与电解质溶液发生电化学作用而造成的破坏现象。
9.3.1 金属的电极电位及腐蚀电池
金属离子水化过程
标准电极电位:活度为1，温度298K，气体分压1.01MP下平衡电极电位。 分为负电性金属，正电性金属。
原电池产生，电位差，可能原因:不同金属，温差，电解质浓度差 9.3.2 金属的极化与钝化
极化现象:腐蚀电池工作后引起的电极电位变化现象，阴极电位降低，阳级电位升高，电池回路电流减小。
钝化:金属表面状态突然变化的过程。铁在浓硝酸，浓硫酸中。可提高金属耐蚀性。 9.3.3 金属元素耐蚀性评定
9.3.3.1 热力学稳定性
金属元素标准电极电位(V) 热力学稳定性 金属元素
<-0.414 不稳定 镁铝锌铁铬
-0.414,0 不够稳定 钼镍
0,+0.815 较稳定 铜 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
>+0.815 稳定 金铂
9.3.3.2 钝化现象
9.3.3.3 生成保护性好的腐蚀产物膜
9.3.4 金属材料耐蚀合金化途径
9.3.4.1 提高金属材料的热力学稳定性 加入热力学稳定性高的合金元素，提高电极电位。 9.3.4.2 减弱金属材料的阳极活性
加入易钝化元素，铁中加入铬。
9.3.4.3 减弱金属材料的阴级活性
减小阴极面积，提高金属材料阴极放氢超电位 9.3.4.4 使金属材料表面生成电阻值大的腐蚀产物膜 钢中加入铜和磷
9.4 金属材料应力腐蚀
材料在静拉伸应力与腐蚀介质作用下发生的破坏现象。 分2类
阳极反应敏感型:金属阳极溶解为基础。
阴极反庆敏感型:阴极吸氢为基础(氢脆) 9.4.1 应力
静拉伸应力
图有效应力与破坏时间
9.4.2 腐蚀介质
有一定组合，钢+氢氧化物
9.4.3 材料
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
合金或含杂质金属。纯铜+0.004%磷
9.4.4 破坏过程
主要是晶间，脆断。也有穿晶，混合
9.5 蒸汽腐蚀
水在铁为催化剂下在400?下发生分解。
4HO+3Fe——>FeO+8H 234
如H不能被流动带走，产生氢脆
影响因素，
防止方法:(1)消除蒸汽停滞现象，(2)加入合金元素，Cr,Mo 9.6 硫腐蚀
锅炉燃料(煤、油)中含有一定量的硫，硫以各种形式存在于烟气中，使锅炉受热面及元件受到
腐蚀。
9.6.1 高压锅炉水冷壁管的硫腐蚀
过程(1)产生自由的硫原子FeS——>FeS+S 2
(2)形成硫化亚铁2HS+SO2——>2HO+3S 22
(3)形成硫化亚铁Fe+S——>FeS
钢材经表面渗铝处理，可提高钢材料耐热性及对某些介质的耐腐蚀性。 9.6.2 锅炉过热器管的高温硫腐蚀
复合硫酸盐在550,700?会与金属反应。
9.6.3 含镍合金钢的硫腐蚀
硫会与钢中的镍发生作用生成NiS，与镍组成易熔共晶体(Ni-NiS)。 2222防止方法在含镍的钢中加入合金元素Cr。
9.6.4 硫的低温腐蚀
低温烟气中有少量SO，与水蒸汽化合成硫酸。 3
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
防止方法:省煤器及低氧燃烧
9.7 钒腐蚀
油燃烧产生的钒氧化物存在于油灰中，高温下会破坏金属的氧化膜。 钢中加入添加剂，镁，氧化镁。
9.8 氧腐蚀
指水或汽水混合物中所含的氧与金属材料之间发生的电化学腐蚀现象。 9.8.1 氧腐蚀原理
铁(标准电极电位-0.44V)与氧构成原电池(+0.4V)。
9.8.2 影响氧腐蚀因素
9.8.2.1 水中的溶解氧量
溶解氧越多，氧腐蚀速度越大
9.8.2.2 水的pH值
PH值越低，腐蚀越严重，PH接近于7时，金属表面生成保护膜，腐蚀速度显著降低。 9.8.2.3 水的温度
温度越高，扩散越快，金属腐蚀越快
9.9 防腐原理
电化学腐蚀是金属腐蚀的更重要更普遍的形式，尽可能减少原电池; 在钢表面形成一层稳定，完整且与钢基体结合牢固的钝化膜;
在形成原电池的情况下，尽可能减少两极间电位差。
第10章 金属材料的疲劳 材料或元件在交变应力(随时间作周期性改变的应力)作用下，经过一段时期后，在内部缺陷或应力集中的部位，局部产生细微的裂纹，裂纹逐渐扩展以致在应力远小于屈服点或强度极限的情air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
况下，突然发生脆性断裂，这种现象称为疲劳，例如频繁进料、出料的周期性间歇操作的设备，
往复式压缩机气缸，应考虑其疲劳失效的可能性( 疲劳分类:
(1) 高周疲劳
低应力，高循环次数。最常见
(2) 低周疲劳
高应力，低循环次数。
(3) 热疲劳
温度变化引起的热应力作用下引起的疲劳破坏。 (4) 腐蚀疲劳
交变载荷与腐蚀介质共同作用下引起的破坏。
接触疲劳 (5)
机件的接触表面在接触应力反复作用下出现表面剥落。
10.1 交变载荷特性
大小或方向或两者同时随时间发生周期性变化的载荷。 交变载荷的特性可用几个参数来表示:
应力循环:交变应力在两个应力极值之间变化一次的过程。 最大应力(ζ):循环中代数值最大的应力。 max
最小应力(ζ):循环中代数值最小的应力。 min
平均应力:(ζ+ζ)/2 maxmax
应力幅:(ζ-ζ)/2 maxmin
不对称系数:r=(ζζ);r=-1对称，r=0脉动;-1
10曲线呈水平,对于铝合金等有色金属则没有明显水平部分。
10.2.3 疲劳断裂的断口特征
脆性断裂，断口无明显塑性变形，贝壳状纹路。
对缺口敏感(材料外缘和芯部纹扩散速度不同)，对缺口不敏感。 10.2.4 金属材料的疲劳抗力指标
10.2.4.1 疲劳极限
材料经无限多次应力循环不断裂的交变应力幅值。
57对于铝合金取Nf>=10,10的应力幅值作为条件疲
劳极限。
同一材料，对称循环疲劳极限也不同，弯曲疲劳极
限(ζ)>拉压疲劳极限(ζ)>扭转疲劳极限(η)。 -1-1p-1n10.2.4.2 疲劳缺口的敏感度
应力集中程度用应力集中系数
缺口对疲劳强度的影响，用疲劳有效应力集中系数Kf 缺口敏感度 ，图，相同缺口半径，材料强度越高，q值越大。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
10.3 疲劳断裂机理
10.3.1 疲劳裂纹的产生
金属所受交变应力大于疲劳极限，在金属表面，晶界及非金属夹杂物处形成滑移带，滑移带中的缺陷或挤入沟处形成应力集中，形成裂纹源。
10.3.2 疲劳裂纹的扩展
第1阶段:从金属表面的驻留滑移带，挤入沟或夹杂物开始，沿最大切应力方向(与主应力呈45?方向)向内部发展。速度慢，每1次循环0.1nm数量级
第2阶段:裂纹扩展方向逐渐转为和主应力垂直的方向，速度快，每1次循环微米数量级。 10.3.3 疲劳裂纹的扩展速率
每次应力循环裂纹的扩展量 ，称为疲劳扩散速率。
典型疲劳裂纹扩展速率曲线图 如下:
分3阶段:
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
7第1阶段: 随 降低迅速降低，至 为0，门槛值 =1,3*10mm 第2阶段:稳定扩展区或亚临界扩展区。
第3阶段:快速扩展， 接近材料Kc(断裂韧性)值，断裂。 材料疲劳裂纹扩展速率
主要研究亚临界扩展速率
Barsom方程
铁素体钢: (疲劳裂纹亚临界扩展区中特性最好) 马氏体钢:
奥氏体钢:
10.4 影响材料疲劳抗力的因素
10.4.1 化学成分和夹杂物的影响
含碳量，合金元素，夹杂
10.4.2 热处理和显微组织的影响
屈氏体(断裂抗力大)>马氏体(脆性在，抗力小)>索氏体(断裂抗力小) 细化晶粒有利于裂纹改向。
10.4.3 应力集中的影响
疲劳裂纹总是出现在应力集中处，应力集中越严重，疲劳强度下降越多。 10.4.4 试件尺寸的影响
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
尺寸大，缺陷多。
10.4.5 表面加工的影响
疲劳裂纹常从零件表面开始产生。表面粗糙度越低，疲劳强度越高。 10.4.6 温度的影响
温度升高，疲劳强度降低。
10.5 低周疲劳特性
反复塑性变形造成的破坏。循环应力高，接近或超过材料的屈服极限。
10.5.1 低周疲劳时的应力-应变曲线
第1阶段出现硬化或软化。
循环硬化:形变抗力在应力循环中增加。(退火钢) 循环软化:形变抗力在应力循环中减小。(冷加工硬化) 第2阶段0.2,0.5倍总寿命循环次数后，应变曲线稳定。 应变量含弹性应变和塑性应变
10.5.2 材料的低周疲劳特性曲线
在低周疲劳条件下，影响材料疲劳寿命的主要参量是应变幅值。图9-33
把 时疲劳寿命称为过渡疲劳寿命 ，重要，是材料疲劳损伤关键指标。
Nf>NT，高周疲劳，提高强度以提高抗疲劳能力;反之，保持一定强度基础上，提高材料塑性和
韧性。
10.5.3 锅炉与压力容器用钢的疲劳设计曲线
锅炉及压力容器在启停过程中会发生压力和温度波动，使材料产生低周疲劳。当以下各项预期的
循环次数总和超过100次，才需对部件进行低周疲劳设计。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(1) 设计的预计压力循环(启停)次数
(2) 压力变化超过设计压力20%的预计压力循环次数。
(3) 部件上距离 两点温度变化有效次数计的循环次数。
(4) 部件的焊烽位于线膨胀系数不同的材料之间，以 时的温度变
化次数计的循环次数。
一些国家均在其设计规范中提出了锅炉压力容器用钢的疲劳设计曲线。 下图为美国ASME规范的疲劳设计曲线图。
10.5.4 影响低周疲劳的主要因素
10.5.4.1 塑性
塑性好的材料，易产生塑性变形，使应力得到重新分布。因此抵抗低周疲劳性能较好。 10.5.4.2 加载频率和保持时间
加载频率降低和保持时间增加会降低材料寿命。
10.5.4.3 晶粒大小
随着晶粒变细，材料的低周疲劳寿命增加。
10.5.4.4 环境介质
高温下，裂纹尖端发生氧化，加速裂纹扩展。
10.6 热疲劳
10.6.1 热疲劳现象
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
材料在加热，冷却的循环作用下，由交变热应力引起的破坏。
热应力
——材料的线膨胀系数
E——材料的弹性模量
10.6.2 材料在承受热疲劳时的应力-应变曲线
热疲劳是塑性变形积累损伤的结果，与低周疲劳具有相似的应变——寿命规律，其破坏特征是相同的。但伴有松驰。
10.6.3 热疲劳与机械疲劳的区别
(1) 除了热应力，还有内部组织变化，使强度和塑性降低。
(2) 温度分布不均，温度梯度大塑性变形大。
(3) 温度高时，穿晶断裂会向晶间断裂过渡。
在相同的塑性变形范围内，热疲劳寿命一般比机械疲劳低。
10.6.4 影响热疲劳的主要因素
10.6.4.1 温度
温度变化幅: ，随着温度幅的增加，材料的热疲劳强度降低，破坏循环次数减少。另外，如果温度幅保持不变，随着平均温度的提高，材料的热疲劳强度也降低。 10.6.4.2 高温保温时间与加热冷却速度
Tmax保持时间越长，热疲劳循环寿命下越多，应力松驰越明显，塑性变形增加。 加热，冷却速度越快，寿命越短
10.6.4.3 环境气氛
氧化性 气氛和燃气中热疲劳寿命明显降低。
10.6.4.4 材料物理性能
线膨胀系数和弹性模量越大，产生的热应力越大;材料的导热系数越小，在材料中产生的温度梯度越大。这些都将导致材料的抗热疲劳能力降低。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
10.6.4.5 材料显微组织
细小的晶粒度有利于抵抗热疲劳;晶界是否有第二相析出，则裂纹易于沿析出相扩展，降低了热
疲劳强度。
10.6.5 热疲劳破坏的断口特征
10.6.5.1 宏观
热疲劳引起的断裂为脆性断裂，伴有少量塑性变形。
10.6.5.2 微观
穿晶或晶间 断裂，裂纹内部往往充满灰色腐蚀物，裂纹扩展过程中产生的氧化或腐蚀。
10.7 腐蚀疲劳
石油贮罐
10.7.1 腐蚀疲劳特性
在任何腐蚀介质中均会发生。
材料的条件腐蚀疲劳极限与其静强度之间不存在直接关系。 10.7.2 腐蚀疲劳机理
滑移-溶解型:在交变应力上升期，滑移台阶露出新鲜表面，被腐蚀。 10.7.3 影响腐蚀疲劳的主要因素
10.7.3.1 加载频率
频率越低，在一定载荷周期数内，材料与腐蚀介质接触时间越长，腐蚀作用越大，材料的腐蚀疲
劳强度越低。
10.7.3.2 平均应力
平均应力增大使腐蚀疲劳裂纹扩展速度增加。
10.7.3.3 组织状态
电化学稳定性，具有马氏体组织碳互钢，对腐蚀疲劳敏感。 10.7.3.4 合金元素
超过5%合金元素，提高耐蚀性
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
10.8 接触疲劳
10.8.1 接触疲劳的类型和破坏过程 类型:
(1) 麻点剥落，深度0.1,0.2mm
(3) 浅层剥落，深度0.2,0.4mm
(2) 深层剥落，裂纹起源在硬化层 10.8.2 影响材料接触疲劳抗力的因素 10.8.2.1 材料中非金属夹杂物
在它们与基体金属的交界处将产生明显的应力集中，在该处形成微裂纹，降低了材料的接触疲劳
寿命。
10.8.2.2 钢的马氏体中碳的质量分数 有最佳含量
10.8.2.3 钢中碳化物的影响
裂纹在碳化物中形成，含量有最佳值。 10.8.2.4 钢的硬度影响
一方面提高强度，塑性变形抗力的增加。另一方面，一旦裂纹源形成，硬度高材料裂纹敏感性强。
10.9 提高材料与机件疲劳强度的途径 10.9.1 合理的疲劳设计
减小应力集中
10.9.2 高疲劳抗力材料的选择
10.9.2.1 提高纯度
减少夹杂物将大大提高疲劳强度。
10.9.2.2 细化晶粒
细化晶粒能显著提高高周疲劳强度和低周疲劳寿命; air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
但在较高的温度下(如在0.5T，T为材料熔点)时，则适当粗的晶粒更为有利。 ff
10.9.2.3 强度，塑性和韧性的合理配合
在不同工作条件下，材料的强度、塑性和韧性都具有相应的最佳配合。
10.9.3 表面强化
10.9.3.1 表面热处理强化
钢经渗碳、氮化和碳氮共渗等化学表面热处理，或高、中频表面感应淬火，提高表面硬度及抗疲
劳强度。
10.9.3.2 表面冷加工硬化
利用机械的方法使表面产生很大的压缩残余应力，从而使其疲劳强度得到显著提高。常方法有:
喷丸和滚压强化。
第11章 合金元素在钢中的作用
随着现代工业和科学技术的不断发展，在机械制造中，对工件的强度、硬度、韧性、塑性、耐磨性以及其他各种物理化学性能的要求愈来愈高，碳钢已不能完全满足这些要求了。 原因 :
(1) 由碳钢制成的零件尺寸不能太大。否则，因淬透性不够而不能满足对强度与塑性、韧性的要求。加入合金元素可增大淬透性。
(2) 用碳钢制成的切削刀具不能满足切削红硬性的要求。用合金工具钢、高速钢和硬质合金。 (3) 碳钢不能满足特殊性能的要求，如要求耐热、耐低温、抗腐蚀、有强烈磁性或无磁性等等，只有特种的合金钢才能具有这些性能。
11.1 合金元素在钢中的存在方式
11.1.1 合金元素与钢中的碳相互作用，形成碳化物存在于钢中
按合金元素在钢中与碳相互作用的情况，它们可以分为两大类:
(1)不形成碳化物的元素(称为非碳化物形成元素)，包括镍、硅、铝、钴、铜等。由于这些元素与碳的结合力比铁小，因此在钢中它们不能与碳化合，它们对钢中碳化物的结构也无明显的影响。 (2)形成碳化物的元素(称为碳化物形成元素)，根据其与碳结合力的强弱，可把碳化物形成元素分成三类。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
1)弱碳化物形成元素:锰
锰对碳的结合力仅略强于铁。锰加入钢中，一般不形成特殊碳化物(结构与Fe3C不同的碳化物称为特殊碳化物)，而是溶入渗碳体中。
2)中强碳化物形成元素;铬、钼、钨
3)强碳化物形成元素:钒、铌、钛
有极高的稳定性，例如TiC在淬火加热时要到l 000C以上才开始缓慢的溶解，这些碳化物有极高的硬度，例如在高速钢中加人钒，形成V4C，使之有更高的耐磨性。 11.1.2 合金元素溶解于铁素体(或奥氏体)中，以固溶体形式存在于钢中 11.1.3 合金元素与钢中的氮、氧、硫等化合，以氮化物、氧化物、硫化物和硅酸盐等非金属
夹杂物的形式存在于钢中
11.1.4 游离态，即不溶于铁，也不溶于化合物:铅，铜
11.2 合金元素对钢的平衡组织的影响
表现在改变铁碳合金状态图
11.2.1 合金元素对钢临界温度的影响
锰、镍、铜使A3线降低，钼、钨、硅、钒使A3线升高。
同样影响A1，影响程度更大，
11.2.2 合金元素对钢共析点(S点)位置的影响
大多数合金使共析点左移，钼钨在质量分数大时使共析点右移。
11.2.3 合金元素对奥氏体相区大小的影响
11.2.3.1 扩大γ区
合金元素与γ-Feα-Fe形成固溶体，常温下为奥氏体组织。Ni，Mn 11.2.3.2 减小γ区
抑制F向A转变，Cr
11.3 合金元素对热处理的影响
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
11.3.1 合金元素对奥氏体化的影响
奥氏体晶粒在铁素体与碳化物边界处生核并长大;剩余碳化物的溶解;奥氏体成分 的均匀化，在高温停留时奥氏体晶粒的长大粗化等过程。在钢中加入合金元素对后三个过程有较大的影响。
(1) 含有碳化物形成元素的合金钢，其组织中的碳化物，是比渗碳体更稳定的合金渗碳体或
特殊碳化物，因此，在奥氏体化加热时碳化物较难溶解，即需要较高的温度和较长的时
间。一般来说，合金元素形成碳化物的倾向愈强，其碳化物也愈难溶解。 (2) 合金元素在奥氏体中的均匀化，也需要较长时间，因为合金元素的扩散速度，均远低于
碳的扩散速度。
(3) 某些合金元素强烈地阻碍着奥氏体晶粒的粗化过程，这主要与合金碳化物很难溶解有关，
未溶解的碳化物阻碍了奥氏体晶界的迁移，因此，含有较强的碳化物形成元素(如钼、钨，
钒，铌、钛等)的钢，在奥氏体化加热时，易于获得细晶粒的组织。 各合金元素对奥氏体晶粒粗化过程的影响，一般可归纳如下:
1)强烈阻止晶粒粗化的元素:钛、铌、钒、铝等，其中以钛的作用最强。 2)钨、钼、铬等中强碳化物形成元素，也显著地阻碍奥氏体晶粒粗化过程。 3)一般认为硅和镍也能阻碍奥氏体晶粒的粗化，但作用不明显。
4)锰和磷是促使奥氏体晶粒粗化的元素。
11.3.2 合金元素对奥氏体分解转变的影响
多数合金元素使奥氏体分解转变的速度减慢，即C曲线向右移，也就是提高了钢的淬透性。 合金元素对马氏体转变的影响
增加冷却时间，降低冷却速度。
另外，合金元素对马氏体开始转变温度(Ms点)也有明显的影
响。多数合金元素均使马氏体开始转变温度(Ms点)降低，其中
锰、铬、镍的作用最为强烈，只有铝、钴是提高Ms点。
11.3.3 合金元素对回火转变的影响
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
合金元素对淬火钢回火转变的影响主要有下列三个方面。
(1)提高钢的回火稳定性
这主要表现为合金元素在回火过程中推迟了马氏体的分解和残余奥氏体的转变，提高了铁素体的再结晶温度，使碳化物难以聚集长大而保持较大的弥散度，从而提高了钢对回火软化的抗力，即提高了钢的回火稳定性。
(2)产生二次硬化
一些合金元素加入钢中，在回火时，钢的硬度并不是随回火温度的升高一直降低的，而是在达到某一温度后，硬度开始增加，并随着回火温度的进一步提高，硬度也进一步增大，直至达到峰值。这种现象称为回火过程的二次硬化。图
回火二次硬化现象与合金钢回火时析出物的性质有关。当回火温度低于约450?时，钢中析出渗碳体，在450?以上渗碳体溶解，钢中开始沉淀析出弥散稳定的难熔碳化物Mo2C、 VC等，使钢的硬度开始升高，而在550,600?左右沉淀析出过程完成，钢的硬度达到峰值。 (3)增大回火脆性
钢在回火过程中出现的第乙类回火脆性(250,400C回火)t即回火马氏体脆性和第二类 回火脆性(450,600,C回火)，即高温回火脆性均与钢中存在的合金元素有关。 11.4 合金元素对氧化与腐蚀的影响
一些合金元素加入钢中能在钢的表面形成一层完整的、致密而稳定的氧化保护膜，从而提 高了钢的抗氧化能力。最有效的合金元素是铬、硅和铝(参看图10-8)。但钢中硅、铝的质量分 数较多时钢材变脆，因而它们只能作为辅加元素，一般都以铬为主加元素，以提高钢的抗氧化性。
钢中加入少量的铜、磷等元素，可提高低合金高强度钢的耐大气腐蚀。 11.5 合金元素对机械性能的影响
11.5.1 金属材料的强化方法
金属材料的强化途径，主要有以下几个方面;
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(1)结晶强化。结晶强化就是通过控制结晶条件，在凝固结晶以后获得良好的宏观组织和显微组织，从而提高金属材料的性能。它包括:
1) 细化晶粒。细化晶粒可以使金属组织中包含较多的晶界，由于晶界具有阻碍滑移变形作用，
因而可使金属材料得到强化。同时也改善了韧性，这是其它强化机制不可能做到的。 2) 提纯强化。在浇注过程中，把液态金属充分地提纯，尽量减少夹杂物，能显著提高固态 金
属的性能。夹杂物对金属材料的性能有很大的影响。在损坏的构件中，常可发现有大量的夹
杂物。采用真空冶炼等方法，可以获得高纯度的金属材料。
(2)形变强化。金属材料经冷加工塑性变形可以提高其强度。这是由于材料在塑性变形后
位错运动的阻力增加所致。
(3)固溶强化(通过合金化(加入合金元素)组成固溶体，使金属材料得到强化称为固溶强化。 (4)相变强化。合金化的金属材料，通过热处理等手段发生固态相变，获得需要的组织结构，使金属材料得到强化，称为相变强化(
相变强化可以分为两类:
1) 沉淀强化(或称弥散强化)。在金属材料中能形成稳定化合物的合金元素，在一定条件下，
使之生成的第二相化合物从固溶体中沉淀析出，弥散地分布在组织中，从而有效地提高材料
的强度，通常析出的合金化合物是碳化物相。
在低合金钢(低合金结构钢和低合金热强钢)中，沉淀相主要是各种碳化物，大致可分为三类。一是立方晶系，如TiC、V4C3，NbC等，二是六方晶系，如M02、W2C、WC等，三是正菱形，如Fe3C。对低合金热强钢高温强化最有效的是体心立方晶系的碳化物。
2) 马氏体强化。金属材料经过淬火和随后回火的热处理工艺后，可获得马氏体组织，使材料
强化。但是，马氏体强化只能适用于在不太高的温度下工作的元件，工作于高温条件下的元
件不能采用这种强化方法。
(5)晶界强化。晶界部位的自由能较高，而且存在着大量的缺陷和空穴，在低温时，晶界阻 碍了位错的运动，因而晶界强度高于晶粒本身;但在高温时，沿晶界的扩散速度比晶内扩散速度大得多，晶界强度显著降低。因此强化晶界对提高钢的热强性是很有效的。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
硼对晶界的强化作用，是由于硼偏集于晶界上，使晶界区域的晶格缺位和空穴减少，晶界自由能降低;硼还减缓了合金元素沿晶界的扩散过程;硼能使沿晶界的析出物降低，改善了晶界状态，加入微量硼、锆或硼+锆能延迟晶界上的裂纹形成过程;此外，它们还有利于碳化物相的稳定。 (6)综合强化。在实际生产上，强化金属材料大都是同时采用几种强化方法的综合强化， 以充分发挥强化能力。例如:
1)固溶强化十形变强化，常用于固溶体系合金的强化。
2)结晶强化+沉淀强化，用于铸件强化。
3)马氏体强化+表面形变强化。对一些承受疲劳载荷的构件，常在调质处理后再进行喷 丸或滚压处理。
4)固溶强化+沉淀强化。对于高温承压元件常采用这种方法，以提高材料的高温性能。 有时还采用硼的强化晶界作用，进一步提高材料的高温强度。 ?
11.5.2 合金元素对正火(或退火)状态钢机械性能的影响
正火状态下钢有铁素体和珠光体组织。固溶强化，结晶强化，沉淀强化。 合金元素不仅影响钢材的强度，同时也影响其韧性。
11.5.3 合金元素对调质钢机械性能的影响
合金元素对调质钢机械性能的影响，主要是通过它们对淬透性和回火性的影响而起作用 的。主要表现于下列几方面。
(1) 由于合金元素增加了钢的淬透性，使截面较大的零件也可淬透，在调质状态下可获得
综合机械性能优良的回火索氏体。
(2) 许多合金元素可使回火转变过程缓慢，因而在高温回火后，碳化物保持较细小的幂颗
粒，使调质处理的合金钢能够得到较好的强度与韧性的配合。
(3)高温回火后，钢的组织是由铁素体和碳化物组成，合金元素对铁素体的固溶强化作用可提高调质钢的强度。
11.6 合金元素对钢的工艺性能的影响
11.6.1 合金元素对焊接性能的影响 :
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
钢的焊接性能，主要取决于它的淬透性、回火性和碳的质量分数。
合金元素对钢材焊接性能的影响，可用焊接碳当量来估算。我国目前所广泛应用的普通低合金钢，其焊接碳当量可按下述经验公式计算。
公式 Cd=C+1/6Mn+1/5Cr+1/15Ni+1/4Mo+1/5V+1/24Si+1/2P+1/13Cu
近年来，对厚度为15、50mm的200个钢种(从碳钢到强度等级为1000MPa级的高强度合金钢)，以低氢焊条进行常温下的Y型坡口拘束焊接裂纹试验。在试验基础上，提出了一个用以估计钢材出现焊接裂纹可能性的指标，称为钢材焊接裂纹敏感性指数户(，其计算公式为
公式 Pc=C+1/30Si+1/20Mn+1/20Cu+1/60Ni+1/20Cr+1/15Mo+1/10V+5B+1/600t+1/60H% 与碳当量公式相比增加了板厚和含氢量。
11.6.2 合金元素对切削加工的影响
金属的切削性能是指金属被切削的难易程度和加工表面的质量。
为了提高钢的切削性能，可在钢中加入一些能改善切削性能的合金元素，最常用的元素是硫，其次是铅和磷。
由于硫在钢中与锰形成球状或点状硫化锰夹杂，破坏了金属基体的连续性，使切削抗力降低，切屑易于碎断，在易切削钢中硫的质量分数可达0.08,,0.30,。
铅在钢中完全不溶，以2,3pm的极细质点均匀分布于钢中，使切屑易断，同时起润滑作用，改善了钢的切削性能，在易切削钢中铅的质量分数控制在0.10,,0.30,。
少量的磷溶入铁素体中，可提高其硬度和脆性，有利于获得良好的加工表面质量。 11.6.3 合金元素对塑性加工性能的影响
钢的塑性加工分为热加工和冷加工两种。
热加工工艺性能通常由热加工时钢的塑性和变形抗力，可加工温度范围、抗氧化能力、对锻造加热和锻后冷却的要求等来评价。合金元素溶入固溶体中，或在钢中形成碳化物，都能使钢的热变形抗力提高和塑性明显降低，容易发生锻裂现象。但有些元素(如钒+铌，钛等)，其碳化物在钢中呈弥散状分布时，对钢的翅性影响不大。另外，合金元素一般都降低钢的导热性和提高钢的淬透性，因此为了防止开裂，合金钢锻造时的加热和冷却都必须缓慢。
冷加工工艺性能主要包括钢的冷态变形能力和钢件的表面质量两方面。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
溶解在固溶体中的合金元素，一般将提高钢的冷加工硬化程度，使钢承受塑性变形后很快地变硬变脆，这对钢的冷加工是很不利的。因此，对于那些需要经受大量塑性变形加工的钢材，在冶炼时应限制其中各种残存合金元素的量，特别要严格控制硫、磷等。另一方面，碳、硅、磷、硫、镍、铬、钒、铜等元索还会使钢材的冷态压延性能恶化。
11.6.4 合金元素对铸造性能的影响
钢的铸造性能主要由铸造时金属的流动性、收缩特点、偏析倾向等来综合评定。它们与钢的固相线和液相线温度的高低及结晶温度区间的大小有关。固、液相线的温度愈低和结晶沮度区间愈窄，铸造性能愈好。因此，合金元素的作用主要取决于其对状态图的影响(另外，一些元素如铬、钼、钒、钛、铝等，在钢中形成高熔点碳化物或氧化物质点，增大了钢液的粘度，降低其流动性，使铸造性能恶化。
11.7 几种常用合金元素在钢中的作用
为了合金化而加入的合金元素，最常用的有硅、锰、铬、镍、钼、钨、钒，钛，铌、硼、铝等。现分别说明它们在钢中的作用。
11.7.1 硅在钢中的作用
(1)提高钢中固溶体的强度和冷加工硬化程度使钢的韧性和塑性降低。
(2) 硅能显著地提高钢的弹性极限、屈服极限和屈强比。这是一般弹簧钢。 (3)耐腐蚀性。硅的质量分数为15,一20,的高硅铸铁，是很好的耐酸材料。含有硅的钢在氧化气氛中加热时，表面也将形成一层SiO2薄膜，从而提高钢在高温时的抗氧化性。 缺点:(4)使钢的焊接性能恶化。
11.7.2 锰在钢中的作用
(1)锰对提高钢的淬透性。
(2)锰对提高低碳和中碳珠光体钢的强度有显著的作用。
(3)锰对钢的高温瞬时强度有所提高。
锰钢的主要缺点是，?含锰较高时，有较明显的回火脆性现象;?锰有促进晶粒长大的作用，因此锰钢对过热较敏感t在热处理工艺上必须注意。这种缺点可用加入细化晶粒元素如钼、钒、air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
钛等来克服:?当锰的质量分数超过1,时，会使钢的焊接性能变坏，?锰会使钢的耐锈蚀性能
降低。
11.7.3 铬在钢中的作用
(1)铬可提高钢的强度和硬度。
(2)铬可提高钢的高温机械性能。
(3)使钢具有良好的抗腐蚀性和抗氧化性
(4) 阻止石墨化
(5) 提高淬透性。
缺点:?铬是显著提高钢的脆性转变温度?铬能促进钢的回火脆性。 11.7.4 镍在钢中的作用
(1)可提高钢的强度而不显著降低其韧性。
(2)镍可降低钢的脆性转变温度，即可提高钢的低温韧性。(3)改善钢的加工性和可焊性。 ‘ :
(4)镍可以提高钢的抗腐蚀能力，不仅能耐酸，而且能抗碱和大气的腐蚀。 11.7.5 钼在钢中的作用
(1)钼对铁素体有固溶强化作用。
(2)提高钢热强性
(3)抗氢侵蚀的作用。
(4)提高钢的淬透性。
缺点:钼的主要不良作用是它能使低合金钼钢发生石墨化的倾向。 11.7.6 钨在钢中的作用
(1) 提高强度
(2)提高钢的高温强度。
(3)提高钢的抗氢性能。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(4)是使钢具有热硬性。因此钨是高速工具钢中的主要合金元素。
11.7.7 钒在钢中的作用
(1)热强性。
(2)钒能显著地改善普通低碳低合金钢的焊接性能。
11.7.8 钛在钢中的作用
(1)钛能改善钢的热强性，提高钢的抗蠕变性能及高温持久强度;
(2)并能提高钢在高温高压氢气中的稳定性。使钢在高压下对氢的稳定性高达600?以上，在珠光体低合金钢中，钛可阻止钼钢在高温下的石墨化现象。因此，钛是锅炉高温元件所用的热强钢中的重要合金元素之一。
11.7.9 铌在钢中的作用
(1)铌和碳、氮、氧都有极强的结合力，并与之形成相应的极为稳定的化合物，因而能细化晶粒，降低钢的过热敏感性和回火脆性。
(2)有极好的抗氢性能。
(3)铌能提高钢的热强性
11.7.10 硼在钢中的作用 ;
(1)提高钢的淬透性。
(2)提高钢的高温强度。强化晶界的作用。
11.7.11 铝在钢中的作用
(1)用作炼钢时的脱氧定氮剂，细化晶粒，抑制低碳钢的时效，改善钢在低温时的韧性，特别是降低了钢的脆性转变温度;
(2)提高钢的抗氧化性能。曾对铁铝合金的抗氧化性进行了较多的研究;4,AI即可改变氧化皮的结构，加入6,A1可使钢在980C以下具有抗氧化性。当铝和铬配合并用时，其抗氧化性能有更大的提高。例如，含铁50,一55,、铬30,一35,、铝10,一15,的合金，在1 400C高温时，仍具有相当好的抗氧化性。由于铝的这一作用，近年来，常把铝作为合金元素加入耐热钢中。 (3)此外，铝还能提高对硫化氢和V2O5，的抗腐蚀性。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
缺点:?脱氧时如用铝量过多，将促进钢的石墨化倾向。?当含铝较高时(其高温强度和韧性较低。
第12章 构件用钢
构件用钢是指用于制造各种大型金属结构(桥梁、船舶、锅炉及压力容器等)的钢材，又称为工程用钢。
工作特点:不作相对运动，长期承受静载作用，有一定使用温度要求，长期与大气或海水接触。 性能要求:
(1) 力学性能:刚度，强度，塑性，缺口敏感性及低温脆性。
(2) 化学性能:耐腐蚀性。
(3) 加工性能:良好的冷变形和焊接性要求。
12.1 构件用钢的力学性能特点
构件用钢力学性能三大特点:屈服现象，冷脆现象和时效现象。
12.1.1 屈服现象
钢材经屈服后(冲压)表面质量下降，一般认为屈服现象与钢中C、N原子
与位错相互作用产生的“柯氏气团”有关。减少钢中C、N原子含量或增加
强碳化物形成元素，抑制柯氏气团形成，可减小屈服产生的表面皱折。
12.1.2 冷脆现象
在低于脆性转变温度(T)时发生脆性断裂。 K
12.1.3 时效现象
时效:构件用钢加热至Ac1以上进行淬火或经塑性变形后，在放置过程中，钢的力学性能和物理性能将随时间变化。通常是强度、硬度提高，塑性韧性下降，脆性转变温度提高。 塑性变形后称应变时效，淬火后称淬火时效，一般气候条件下称自然时效，较高温度下称人工时效。
冶标YB30-64规定了低碳钢应变时效敏感性的试验方法。通常把钢在应变时效前后的冲击韧性之百分比C作为钢的时效敏感性的衡量标准:
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
公式
钢材应变时效敏感性主要与固溶于α-Fe中的少量C、N原子有关，特别是N。因此，应控制C、
N含量，加入强碳，氮化物形成元素。
12.2 构件用钢的工艺性能
12.2.1 构件用钢的冷变形性能
构件用钢需要冷变形。冷变形后，强度增高，塑性降低。 三层含义
(1) 变形抗力，决定钢材制成必要开头的部件的难易程度。 (2) 承受一定量的塑性变形时产生开裂或其它缺陷的可能性。 (3) 钢材在冷变形后性能的变化。
12.2.2 构件用钢的焊接性能
用碳当量和焊接敏感性系数衡量。
12.3 构件用钢耐大气腐蚀性能
12.3.1 大气腐蚀过程
微电池现象。
12.3.2 提高构件用钢耐大气腐蚀的途径
(1)减少微电池数量
(2)提高基体的电极电位
(3)得用钝化效应
12.4 碳素构件用钢
普碳钢分为Q195，Q215，Q235，Q255，Q275。钢材厚度<16mm的屈服强度。 按脱氧程度和浇注方法分为沸腾钢，镇静钢和半沸腾钢。 镇静钢:偏析程度小，含气体量少，质量较高。成材率低，成本高。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
沸腾钢:成材率高，成本低。冲击韧性，冷脆倾向性，时效敏感性和焊接性差。 半沸腾钢介于镇静钢和沸腾钢之间。
沸腾钢水韧处理降低时效。普碳钢在950?加热后水冷和400?回火处理。 生产上为了适应特殊用途需要，在普碳钢基础上进一步提出某些特殊的要求，从而形成一系列专用的构件用钢。
锅炉用钢20g,22g
船舶用钢C10,C20
12.5 普通低合金结构钢
加入少量合金，减轻结构质量。
按屈服强度高低分为300Mpa，350Mpa,400,450,500,650Mpa。
化学成分特点:
(1) 低碳低合金元素，基本上不加Cr和Ni。
(2) 主加合金元素是Mn。
(3) 辅加合金元素Al,V,Ti,Nb
(4) 加入Cu和P防大气腐蚀
(5) 稀土元素脱硫去气，净化钢材，改善夹杂物的形成与分布，从而改善钢的机械性能和工
艺性能。
12.6 进一步提高普低钢力学性能途径
12.6.1 发展低碳贝氏体型普低钢
贝氏体型普低钢焊接性好。
14MnMoV,14MnMoVBRe,14CrMnMoVB
加入推迟珠光体转化的合金元素，从而保证热轧空冷(正火)条件下获得下贝氏体组织。 0.5%Mo+0.003%B
12.6.2 采用低碳索氏体型普低钢
易于焊接
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
低碳低合金钢淬火获得低碳马氏体+高温回火=低碳回火索氏体组织。
美国T-1型钢
12.6.3 控制轧制的应用
控制轧制:将普低钢加热至高温(1250,1350?)进行轧制，但终轧温度控制在Ar3附近。 主要目的是细化晶粒，提高轧钢强韧性。
加入的Nb,V元素，产生显著沉淀强化效应，冷脆倾向增大。
12.6.4 发展针状铁素体型普低钢
(1)通过轧制后冷却时形成非平衡的针状铁素体，提供大量的位错亚结构，为以后碳化物的弥散析出创造条件，并可保证夺钢管在原板形成时有较大的加工硬化效应，以防止因包申格效应引起的强度降低。
(2)利用Nb(C、N)等为强化相，使之在轧制后冷却过程中，以及在575,650?时效时从铁素体中弥散析出造成弥散强化。
附近)，并使在900?以下的形(3)采用控制轧制细化晶粒，将终轧温度降至740,780?(Ar3
变量达到65%以上，在每道轧制后用喷雾快冷，以防止碳化物从奥氏体中析出而减弱时效强化效果。
第13章 有色金属及其合金
金属一般分为两大类:一类为黑色金属，包括铁、铬、锰;另一类为有色金属，包括除铁、铬、锰以外的所有金属。但习惯上，人们常常把除铁和钢以外的金属及其合金称作为有色金属。 有色金属具有许多优良的性能，如密度小、比强度大、比模量高、耐热、耐腐蚀以及良好的导电性和导热性。同时许多有色金属又是制造各种优质合金钢和耐热钢所必需的合金元素，因此有色金属在金属材料中占有重要韵地位，是现代航天、航空、原子能、计算机、电子、汽车、船舶、石油化工等工业必不可少的材料。例如，铝、镁、钛等金属及其合金，以密度小、比强度与比模量高的特性而在运载火箭、卫星、飞机、汽车、船舶上获得广泛应用，是制造其中许多结构件和零、部件的主要材料;再如，银、铜、铝等有色金属，导电性和导热性优良，是电力、电器工业和仪表工业不可缺少的材料;又如，铜和钛具有良好的抗蚀性，是石油化工和航海工业所必需的优良耐蚀材料。
本章主要介绍目前工程上应用广泛的铝、镁、铜、钛及其合金和镍基合金，重点讨论这些材料的air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
合金化和热处理原理，以及典型金属和合金的成分、组织、性能及相互关系、工艺特性与实际应用，并简单介绍这些有色金属材料的新近发展。
13.1. 铝及铝合金
铝是地壳中蕴藏量最多的金属元素，其总储量约占地壳重量的7(45,。铝及铝合金的产量在金属材料中仅次于钢铁材料而居第二位。
13.1.1. 纯铝
13.1.1.1. 纯铝性能和优点:
(1) 铝很轻，它的比重为2.7。铝经常作为各种轻质结构材料。
(2) 导电性和导热性较好，仅次于银、铜和金，居第四位。
(3) 塑性好(Ψ=80%)可通过冷或热的压力加工制成各种型材;如丝、线、箔，片、棒等这种
特性与锅具有面心立方品格结构有关。
(4) 抗大气腐蚀性能好，因为在铝的麦面能生成一层极致密的氧化铝薄膜，隔绝铝和氧的接
触，而阻止铝表面的进一步氧化。
(5) 强度很低，45MPa，冷变形加工硬化后强度可提高到100Mpa。
13.1.1.2. 纯铝编号
L+顺序号组成。
我国工业纯铝的牌号是依其杂质的限量来编制的，如L1、L2、L3等，数字越小纯度越高。高纯铝用L0，L00表示，其后所附顺序数字愈大，其纯度愈高，如L04的含铝量不小于99.996%。 13.1.1.3. 纯铝用途
电线，容器，日用炊具，铝基合金。
13.1.2. 铝的合金化
纯铝强度低，最常加入合金元素有
Cu:固溶强化和沉淀强化。
Mg:固溶强化，抗腐蚀。含量大沉淀强化。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
Si:过剩相强化。
Mn:抗腐蚀。
Zn:固溶强化，抗腐蚀。
Li:降低合金元素密度，提高弹性模量。
微量合金元素:Ti,Zr,Cr,V:组织细化
强化。
13.1.3. 铝合金分类 (右图)
根据合金成分和生产工艺，将工业用铝
合金分为变形铝合金和铸造铝合金。
变形铝合金:铝合金铸锭经热变形或冷
变形加工后再使用，有良好的成形性
能。
铸造铝合金:直接浇铸成形，有良好的
铸造性能。
D’和D是两类合金的分界线。
溶质成分低于D点合金，加热至固溶线以上温度可以得到均匀的单相,固溶体，塑性好，变形铝合金。成为位于D’右的合金，有共晶组织，适于作铸造铝合金。
变形铝合金又分为可热处理强化和不可热处理强化，溶质成分位于F点以左的合金，其固溶体成分不随温度而变化，不能借助于时效处理强化，称为不可热处理强化的铝合金。溶质成分位于FD之间的合金，其固溶体成分随温度发生变化，可进行时效沉淀强化处理，称为可热处理强化的铝合金。
13.1.4. 铝合金的热处理
铝合金在使用前一般需经热处理，主要工艺方法有退火，淬火和时效。 退火:自学
淬火: 自学
时效:经一段间，材料强度发生变化的过程。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
时效与时效时间外，还受到时效温度，淬火温度，淬火冷却速度和淬火转移时间以及合金中空位、位错等晶体缺陷的影响。
强化相:～相CuAl2
β相Mg2Si
S相Al2CuMg
W相Al2CuMgSi
T相Mg3Zn3Al2
,相Mg2Zn
时效强化过程:
第1阶段:形成溶质原子(铜)的富集区——GP[I]区。随着GP[I]区的形成，将引起以铝为基的α固溶体的严惩畸变，使位错运动受到阻碍，提高了例金的强度。
第2阶段:GP区有序化——GP[II]区。随着时间的延续，溶质原子(铜)继续向GP[I]区扩散富集并有序化而形成GP[II]区。GP[II]区的化学d成分接近CuAl2具有正方晶格，常用～''表示。与形成GP[I]区相比，形成GP[II]区，将引起以铝为基的α固溶体的更严重的畸变，使位错运动受到更大的阻碍，从而进一步提高了例合金的强度。
第3阶段:溶质原子(铜)继续富集，以及～'相的形成。随着时间的延续，铜原子继续富集，在第2阶段中所形成的～''将逐渐达到的CuAl2化学成分，并部分地与母相α固溶体的晶格脱离联系，而形成一种过渡相——～'。随着～'相的形成，α固溶体的晶格畸变将减轻，对位错的阻碍亦将减少，于是合金向软化。
第4阶段，稳定的～相的形成与长大。时效过程的最后阶段是形成稳定的～相。在此阶段，～相与母相α相固溶体的晶格完全脱离联系，使α固溶体的晶畸变大为减轻，时效所产生的强化效果便显著减弱，合金发生软化，这种现象称为“过时效”。
13.1.4.1. 变形铝合金的热处理特点
变形铝合金中除防锈铝外，硬铝、超硬铝和锻铝均可进行时效强化热处理，根据强化相不同，最佳的强化效果工艺条件也不同。
13.1.4.2. 铸造铝合金的热处理特点
铸造铝合金热处理的目的是改善铸件的组织和稳定尺寸，同时改善切削性能。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
与变形铝合金相比，其热处理有两个特点: (1) 固溶处理和时效处理保温时间长; (2) 淬火液的温度要求较高，以避免开裂。 13.1.5. 变形铝合金
13.1.5.1. 防锈铝LF
Al-Mn系，Al-Mg系
13.1.5.2. 硬铝LY
与防锈铝相比，多了Cu，强化，腐蚀性变差 13.1.5.3. 超硬铝LC
T相和,相 强化作用
13.1.5.4. 锻铝LD
热塑性好
13.1.5.5. 铝锂合金
质轻
13.1.6. 铸铝ZL
铸造性好，可铸出复杂形状，抗腐蚀性好，切削加工性好。
(1)铝硅系铸铝合金
(2) 铝铜系铸铝合金
(3) 铝镁系铸铝合金
(4) 铝稀土系铸铝合金
(5) 铝锌系铸铝合金
13.2. 镁及镁合金
镁是地壳中含量第3的金属元素。
13.2.1. 纯镁
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
3质轻 :密度为1.74g/cm
抗腐蚀性差 :在空气中易氧化
强度低 :不作结构材料
塑性差:延伸率仅为10%左右
13.2.2. 镁合金
强化途径:固溶强化，时效强化，细晶强化和过剩相强化。 加入合金元素:Al,Zn,Mn,Zr及稀土元素。 镁合金分为变形镁合金和铸造镁合金。
变形镁合金:MB1，MB2-MB8，MB15。Mg-Zn系，Mg-Al-Zn系，Mg-Zn-Zr系。
铸造镁合金:ZM。
高强度铸造镁合金和耐热铸造镁合金。
热处理特点:
(1) 组织粗大，淬火加热温度低
(2) 合金元素在镁中扩散速度慢，淬火加热时间长 (3) 易产生不平衡组织，淬火加热速度不宜过快。 (4) 人工时效，析出沉淀相速度快。
(5) 镁氧化倾向大，炉内要有保护气氛。 13.3. 铜及铜合金
13.3.1. 纯铜(紫铜 )
(1)导电导热性好
(2)抗腐蚀性
(3)强度低，塑性好。
(4)优良加工性和焊接性能。
(5)牌号:T1(>99.95%)，T2，T3，T4
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
13.3.2. 铜合金
强化途径:固溶强化，时效强化和过剩相强化。 主要加入合金元素:Zn,Al,Sn,Mn,Ni。
根据化学成分分三类:
黄铜:锌为主要元素。
黄铜性能有三个特点:
(1) 强度和延伸率与其中的含锌量有密切关系。图 (2) 黄铜的铸造性能好。
(3) 黄铜的抗蚀性好。
青铜:除锌和镍的其它元素为主要合金元素。 白铜:镍为主要元素
13.4. 钛及钛合金
含量居第4位，因熔点高，化学性质活泼，冶炼困难，未能作为结构材料使用。
抗腐蚀性 好。
13.4.1. 钛的合金化
(1)扩大α相区
(2)扩大β相区
13.4.2. 钛合金分类
根据钛合金在退火状态下的相组成，将其分为a型和B型和(a+B)型。
以TA，TB，TC表示。
α型 :
主加元素为Al，其次是Sn,Zr。具有高温稳定性。 β型 :
主加元素Mo,V,Mn,Cr,Fe。具有高强度。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(a+β)型 :
介于两种之间
第14章 金属材料的加工工艺性能 下料(毛坯)——热处理——粗加工——热处理(调质)——精加工(表面处理)(——热处理)
毛坯制造方法有铸造，焊接，成形。
本章主要讨论铸造，锻造，焊接，热处理及切削加工性能。 14.1. 金属材料的铸造性能
铸造性能通常指流动性，收缩性，铸造应力，偏析，吸气倾向和裂纹敏感性。 铸造一般采用合金，合金晶粒小。
14.1.1. 影响合金流动性因素
影响因素:合金化学成分，浇铸温度和铸型填充条件。
合金化学成分:
含碳量:纯铁流动性好，含碳量越大，流动性越差。2%左右流动性最差，铸铁中，共晶成分铸铁
流动性最好。
合金成分中凡能形成高熔点夹杂物的元素均会降低合金的流动性。 灰铁中MnS熔点为1620，不利于流动。
P可形成Fe-FeP-FeC，熔点为950，利于流动。 33
14.1.2. 铸件的收缩
14.1.2.1. 铸铁的缩孔与缩松
含碳量增加，析出石墨有利于消除此类现象
14.1.2.2. 铸件的裂纹
冷裂和热裂，P和S
合金强度提高，产生裂纹倾向增大。
14.2. 金属材料的锻造性能
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
可锻性:塑性和变形抗力
14.2.1. 莱氏体高合金工具钢
锻造目的是打碎钢中粗大的共晶碳化物。锻后缓冷(炉冷)防止裂纹产生。 14.2.2. 不锈钢的锻造
不锈钢由于其组织特殊，注意锻后热处理工艺
晶间腐蚀
475?脆性:含Cr量大于15%的高Cr钢在400-525?范围内长时间停留或缓冷，Cr原子有序化，
与母相共晶格引起较大的晶图畸变引起大的内应力。
马氏体不锈钢:缓冷至600?左右空冷，以免发生马氏体相变。 铁素体和奥氏体不锈钢:在晶间腐蚀及475?脆性温度范围内快冷(空冷)。 14.2.3. 高温合金锻造
高温合金在高温下有较大的变形抗力及较低的塑性。模具坚固，功率大。 对锻造温度敏感，锻后堆放空冷。
14.2.4. 有色金属锻造
铝:锻造温度窄。
镁:锻造温度窄，传热快，易冷却，模具需预热。
铜:锻造温度窄，模具需预热，锻造时需保护，避免氧化。
钛:变形抗力大，化学性质活泼，注意保护。
14.3. 金属材料焊接性能
电弧焊，电渣焊，磨擦焊，钎焊，爆炸焊等
钎焊:用在接触处熔化诸如黄铜和钎焊料之类的非铁填充金属(其熔点低于基体金属的熔点)来焊接金属。
14.3.1. 碳钢及合金钢焊接
低碳钢，低合金钢焊接性好。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
对于中高碳钢和合金钢采取焊前预热和焊后热处理。 改善组织并消除焊接应力。
14.3.2. 不锈钢焊接
奥氏体不锈钢:考虑晶间腐蚀。
马氏体不锈钢:焊接后焊缝区在空冷条件下得到马氏体组织，焊前预热(200-400?)焊后热处
理，加热至730-790?后缓冷至540?，空冷。 铁素体不锈钢:焊前预热，焊后热处理(730-840?) 14.3.3. 有色金属的焊接
铜:焊接性能差，采用钎焊。
铝:氩弧焊，焊件表面要求高。
钛:自动焊，表面要求高。
14.4. 金属材料的加工性
工件机加工难易程度称为材料的加工性。
影响因素:加工性与金属材料的化学成分，硬度，韧性，导热性，金相组织和加工硬化能力等因
素有关。
14.4.1. 化学成分的影响
含碳量
降低钢的强度和硬度的元素:S，Al
提高钢的强度和硬度的合金元素:
石墨化:游离石墨改善加工性。
14.4.2. 组织与热处理工艺的影响
组织不同，机械性能不同，加工性不同。
珠光体，索氏体，马氏体，加工性下降。
衡量材料切削加工性能的优势常用相对加工性Kr指标衡量。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
表14.2 材料切削加工性分级
加工性等相对加工性名称及种类 代表性材料 级 Kr
很容易切削材一般有色金5-5-5铜铝合金，9-4铝铜合金，铝镁合1 ,3.0 料 属 金
2 易切削钢 2.5,3.0 15Cr退火ζb=380,450MPa，
容易切削材料 自动机钢ζb=400,500MPa， 3 较易切削钢 1.6,2.5 30钢正火ζb=450,560MPa，
一般钢及铸4 1.0,1.6 45钢，灰铸铁
铁 普通材料 2Cr13调质ζb=850MPa，
稍难切削材35钢ζb=900MPa， 5 0.65,1.0 料
较难切削材6 0.5,0.65 45Cr调质ζb=1050MPa， 料 65Mn调质ζb=950,1000MPa， 7 难切削材料 难切削材料 0.15,0.5 50CrV调质1Cr18Ni9Ti某些钛合金， 很难切削材某些钛合金，铸造镍基高温合金， 8 ,0.15 料
不同级织，不同硬度对不同切削加工操作(如车，铣，刨，镗，拉等)切削加工性是不同的。 如回火索氏体的中碳钢，车削加工性较好，钻削加工性中等，拉，拨加工性较差。 14.4.3. 热处理工艺性能
机床主轴
在选用机床主轴的材料和热处理工艺时，必须考虑以下几点:
(1) 受力的大小。不同类型的机床，工作条件有很大差别，如高速机床和精密机床主轴的工
作条件与重型机床主轴的要作条件相比，无论在弯曲或扭转疲劳特性方面差别都很大。 (2) 轴承类型。如在滑动轴承上工作时，轴颈需要有高的耐磨性。
(3) 主轴的形状及其可能引起的热处理缺陷。结构形状复杂的主轴在热处理时易变形甚至开
裂，因此在选材上应给予重视。
主轴是机床中主要零件之一，其质量好坏直接影响机床的精度和寿命。因此必须根据主轴的工作条件和性能要求，选择用钢和制定合理的冷热加工工艺。
1、 机床主轴的工作条件和性能要求。该主轴的工作条件如下:
(1) 承受交变的弯曲应力与扭转应力，有时受到冲击载荷的作用;
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(2) 主轴大端内锥孔和锥度外圆，经常与卡盘、顶针有磨擦;
(3) 花键部分经常有碰撞或相对滑动。
由此定出技术条件:
(1) 整体调质后硬度应为HB200,230，金相组织为回火索氏体;
(2) 内锥孔和外圆锥面处硬度为HRC45,50，表面3,5mm内金相组织为回火屈氏体和少量回
火马氏体;
(3) 花键部分的硬度为HRC48,53，金相组织同上。
2、 选择用钢
C515车床属于中速，中负荷，在滚动轴承中工作的机床，因此选用45钢。 3、 主轴工艺路线
下料——锻造——正火——粗加工(外圆余留4,5mm)——调质——半精车外圆(余留2.5,3.5mm)，钻中心孔，精车外圆(余留0.6,0.7mm，锥孔留余0.6,0.7mm)，铣键槽——局部淬火(锥孔及外锥体)——车定刀槽，粗磨外圆(余留0.4,0.5mm)，滚铣花键——花键淬火——精磨。
4、 热处理工序作用
正火处理是为了得到合适的硬度(HB170,230)，以便机加工，改善锻造组织，为调质作准备。 调质处理是为了主轴的综合机械性能和疲劳强度，调质后硬度为HB200,230，组织为回火索氏体。
内锥孔和外圆锥面部分经盐浴局部淬火和回火后得到所要求的硬度，以保证装配精度和耐磨性。 5、 热处理工艺
调质中淬火时由于主轴各部分的直径不同，应注意变形问
题
快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题
。调质后变形虽可用校直来修正，但校直时的附加应力对主轴精加工后的尺寸稳定性是不利的。为减小变形，应注意淬火操作方法。可采取预冷淬火和控制水中冷却时间来减小变形。
花键部分高频淬火以减小变形和达到硬度要求。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
经淬火后的内锥孔和外圆锥面部分需经260,300?回火，花键部分需经240,250?回火，以消除淬火应力并达到规定的硬度值。
球铁代替45钢，硬度HRC52,58低，变形量小。
第15章 锅炉及压力容器常用钢材
15.1. 锅炉及压力容器对钢材性能的要求
按工作条件分为两大类:
一、用以制造室温及中温承压元件的钢板与钢管
具有特点:
1 有较高的室温强度
通常以屈服极限σ和强度极限σ为设计依据，要求有较大的σ和σ良好的韧性性能 sbsb
材料需具有足够的韧性防止脆性断裂，在考虑强度的同时也不能忽略韧性， (1) 材料的韧性通常用冲击韧性值α表示。 k
压力容器用钢的冲击韧性要求
2冲击韧性值α(N?m/cm) k
20? -40?
>=60 >=35
(2)还需要考虑时效韧性
时效就是钢材经冷加工变形后，在室温或较高温度下，冲击韧性随时间变化。通常在200-300?，冲击韧性值显著降低。一般要求下降率不超过50%。
由于容器断裂过程包括在缺陷处形成裂纹和裂纹扩散两个阶段，相应两种防止断裂方法 (1)选用具有足够韧性的钢材以防止裂纹产生，要求如上表所示
(2)选用韧性更高的材料，以求在裂纹产生后能够阻止裂纹扩展。(要求温度比无塑性转变温
度NPT高一定数值，例如元件的设计应力为屈服极限σ一半时，要高17? s
3 较低的缺口敏感性
制造过程中，开孔和焊接会产生局部应力集中，要求材料有较低的缺口敏感性，以防止产生裂纹
4 良好的加工工艺性能和焊接性能
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
由于焊接热循环作用，会
(1)降低热影响区材料的韧性、塑性
(2)在焊缝内产生各种缺陷
其中(1)、(2) 均会产生裂纹
在选材料时需考虑
(1)材料中碳的当量值(保证材料具有较好的可焊性) (2)适当的焊接材料和焊接工艺
(3)材料具有良好的塑性(碳钢和碳锰钢δ不低于16%，合金钢δ不低于14%) ss(4)良好的低倍组织
(5)钢材的分层、非金属夹杂物、气孔、疏松等缺陷尽可能减少(防止裂纹的产生)
二、用以制造高温承压元件的钢管
1 具有足够的蠕变强度、持久强度和持久塑性
通常以持久强度为设计依据，保证在蠕变的条件下安全运行 2 具有良好的高温组织稳定性
长期高温下不发生组织变化
3 具有良好的的高温抗氧化性
要求材料在高温条件下的氧化腐蚀速度小于0.1mm/a 4 具有良好的加工工艺性
要求冷加工性(冷态弯曲)和焊接性
15.2. 锅炉与压力容器用钢的分类
一、工作温度低于500?的钢材
碳素钢和低合金结构钢
1 铁素体-珠光体结构钢
屈服强度σ为300-450MPa s
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
16Mn，15MnV，15MnVN加入合金元素，固溶强化，结晶强化作用 2 低碳贝氏体类型钢
屈服强度σ为500-700Mpa s
14CrMnMoVB延缓奥氏体分解，得到贝氏体，增加强度 3 马氏体型调质高碳钢
屈服强度 为600Mpa以上
18MnMoNb和14MnMoNbB正火加回火，有良好的低温韧性 二、工作温度高于500?的钢材
低合金热强钢和奥氏体不锈钢
1 低合金珠光体热强钢
15CrMo和12Cr1MoV，结晶强化，沉淀强化
2 低合金贝氏体热强钢
12Cr2MoWVTiB和12Cr3MoVSiTiB，特点:合金数量多而量少，高温强度高，抗氧化性强
3 奥氏体不锈钢
18-8型铬镍奥氏体不锈钢:1Cr18Ni9Ti和0Cr18Ni9Ti，高温强度高，抗氧化性强，且具有很高
的韧性和较好的加工工艺性
15.3. 碳素钢
一、碳素钢中主要成分对性能的影响
1 碳的影响
碳增加，强度增大，塑性减少，可焊性变差，时效敏感性降低 2 锰的影响
脱氧(FeO)脱硫，改善热加工性能
3 硅的影响
脱氧
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
4 硫的影响
热脆性
5 磷的影响
冷脆性
6氧的影响
降低强度、塑性
7 氮的影响
提高强度、硬度，降低塑性
8 氢的影响
氢脆
二、碳钢的分类
化学成分:高(含碳量在于0.65%)、中(含碳量0.25-0.65%)、低碳钢(含碳量小于0.25%)
用途:普通碳素结构钢、优质碳素结构钢和碳素工具钢 1 普通碳素结构钢
甲类钢:按机械性能供应(A)，钢板，角钢等 2 优质碳素结构钢
按机械性能和化学成分供应
含碳量低:钢板、容器、螺钉、螺母
含碳量中:齿轮、轴
含碳量高:弹簧、钢丝绳
3 碳素工具钢(T)
高硬度和耐磨性，制造刀具、量具、模具 三、锅炉与压力容器常用碳素钢
承压元件主要使用低碳钢，因为塑性、韧性、加工工艺性和可焊性好
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(1) 优质碳素结构钢
10号和20号无缝钢管
20号钢含碳量比10号钢多一倍，强度高，屈服极限σ和强度极限σ高20%，时效敏感性低，sb
多采用20号钢
(2) 专用碳素钢
A3g A3R 15g 20g，冲击韧性好，金属表面和内部缺陷少
15.4. 普通低合金结构钢
低合金钢是在碳素钢的基础上加入少量Si,Mn,Cu,Ti,V,Nb,P等合金元素构成的，它的含碳量较低，多数小于0.2%。其组织多数仍为F+P。由于少量合金元素的加入可以大大提高钢材的强度，并改善了钢材的耐腐蚀性能和低温性能。
低合金钢可轧制成各种钢材，如板材，管材，棒材和型材等。它广泛用于制造远洋轮船、大跨度桥梁，高压锅炉，大型容器，汽车，矿山机械及农业机械等。
大型化工容器材料采用16MnR，生量比碳钢可减轻1/3。用15MnV制造球形贮罐，与碳钢相比节省45%。
焊接
15.5. 低合金热强钢
在原油加热，裂解，催化设备中，常用到许多能耐高温的钢材。如裂解炉管，要求承受650,800?高温。
20号钢在540?下于氧化性气体中，因氧化强度只有50MPa。因为石墨化。 常用的抗氧化钢
——Cr13SiAl,Cr25Ti,Cr17Ti,Cr25Ni2
热强钢
——12CrMo,Cr5Mo,1Cr18Ni9Ti,Cr25Ni20
15.6. 不锈耐酸钢
是不锈钢(耐大气)和耐酸钢(不锈)的总称，
铬不锈钢——1Cr13多用作化工机器中受力大的耐蚀零件，如轴，活塞杆，阀件，螺栓，浮阀等 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
0Cr13,Cr17Ti F组织，有良好塑性
铬镍不锈钢——1Cr18Ni9 18-8不锈钢
有较高的抗拉强度，较低屈服点，极好的塑性和韧性，焊接性能和冷弯成型性能好，用来制造贮罐，塔器，反应釜，应用最广。
15.7. 低温用钢
深冷分离，空分，液化气贮罐低温使用。
低温钢平均含碳量0.08,0.18%，单相F组织，加入适量的Mn,Al,Ti,Nb,Cu,V,N等元素改善钢的综合机械性能。
常用低温用钢
1) 低合金低温用钢
16MnDR -40? 机械性能优于一般低碳钢
2) 镍钢
2.25% -60?
3.5% -100?
9% -200?
3) 高锰奥氏体钢
15Mn25Al4 其中Mn是形成A的基本元素，Al作为稳定A的元素。
4) 铬镍奥氏体不锈钢
18-8奥氏体不锈钢
国外低温设备用钢，以高铬镍为主，其次用镍钢，铜，铝。
第16章 工具钢
16.1 概述
工具钢是用以制造各种加工工具的钢种。根据用途不同(工具钢可分为刃具用钢、模具围钢和量具用钢。按化学成分不同(工具钢又可分为碳素工具钢、合金工具钢和高速钢。
各类工具钢由于工作条件和用途不同(所以对性能的要求也不同。但各类工具钢除飓有各自air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
的特殊性能之外(在使用性能及工艺性能L也有许多共同的要求。如高硬度、高磨性是工具例最重要的使用性能之一。工具若没有足够高的硬度是不能进行切削加工的 。否则，在应力作用下工具的形状和尺寸都要发生变化而失效。高耐磨性则是保证和提高工具寿命的必要条件。
除了上述共性之外，不同用途的工具钢也有各自的特殊性能要求、例如，刃具钢除要求高硬度。高耐磨性外(还要求红硬性及一定的强度和韧性。冷模具钢要求高硬度、高耐磨性、较高的强度和一定的动化热模具钢则要求高的韧性和耐热疲劳性及一定的硬度和耐磨性。对于量具钢(除要求具有高硬度、高耐磨性外(还要求高的尺寸稳定性。
在化学成分上(为了使工具钢尤其是刀具钢具有高的硬度，通常都使其含有较高的碳(含碳量为0.65% ,1.55% )，以保证淬火后获得高碳马氏体、从而得到高的硬度和切断抗力，这对减少和防止工具损坏是有利的(此外(高的合碳量还可以形成足够数量的碳化物以保证高的耐磨性、所加入的合金元素主要是使钢具有高硬度和高耐磨性的一些碳化物形成元素如Cr、W、M。、V等。有时也加入Mn和Si，其目的主要是增加钢的淬透性以达到减少钢在热处理时的变形(同时增加钢回火稳定性。对于切削速度较高的刃具常加入较多的W、Mo、V、Co等合金元素(以提高钢的红硬性 。
工具钢对钢材的纯洁度要求很严(对S、P含量一般均限制在0.02,,0(03,以下(属于优质钢或高级优质钢。钢材出厂时(其化学成分、脱碳层、碳化物不均匀度等均应符合国家有关标准规定、否则会影响工具钢的使用寿命
生产实践表明刃具钢理想的淬火组织应是细小的高碳马氏体和均匀细小的碳化物(因此刃具钢在热处理前都应进行球化退火，以使碳化物呈细小的颗粒状。且分布均匀。这不仅对保证钢的优良切削性、耐磨性和韧性有利(而且对热处理工艺(如防止或减轻过热敏感性、变形、淬裂倾向等)亦十分有利。
经球化退火后的组织为铁素体(其基体上分布着细小均匀的粒状碳化物。工具钢因含碳量较高，因此(在热处理淬火加热时应在盐浴炉或保护气氛条件下进行加热(否则易产生氧化 脱碳现象。值得注意的是应在淬火后及时进行回火。
对于一种工具(选用什么样的钢材合理(首先应从工具的工作条件、失效形式及性能要求出发，然后选择合适的钢种(最后再制订正确的热处理工艺。同时还应考虑工具钢的工艺性能包括热加工性能、切削加工性能和热处理工艺性能(如钢的淬透性、淬硬性、过热敏感性、脱碳倾向性和热处理变形性能等)。
应该注意至，一种钢可以兼有几种用途(如T8钢既可以用来制造简单模具(也可以制造夹具、木工工具、钳工工具等。这些因素在选用工具钢时(均应予以考已本章主要介绍刃具钢、模air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
具钢的工作条件、失效形式及其性能要求(阐述各类钢种的衍变、选材原则及其发挥材料性能潜力的途径。
16.2刃具用钢
刃具钢是用来制造各种切削加工工具的钢种、刃具的种类繁多加车刀、铁刀刨刀、钻头、丝锥及极牙等。其中车刀最具有代表性，车刀的工作条件基本能反映各类刃具工作条件的特点. 一、刃具钢的工作条件及性能要求
刃具在切削过程中(刀刃与工件表面金属相互作用(使切屑产生变形与断裂(并从工件整体上剥离下来。故刀刃本身承受弯曲、扭转、剪切应力和冲击、振动等负荷作用(同时还要受到工件和切屑的强烈摩擦作用。由于切屑层金属的变形以及刃具与工件、切属的摩擦产生大量的摩擦热(均使刃具温度升高一切削速度越快(则刃具的温度
越高，有时刀刃温度可达600?左右。
刀刃温度的升高(?T)与切削速度(v)、走刀量(S)和切削进对深度(t)之间有如下经验关系
abc公式 ?T=C?V?S?t
式中a、b、c、C均为随刃具与工件材料而异的常数。其中对对对温度升高的影响以切削速度(v)的影响最大。
刀刃的失效形式写多种(有的刀具刀刃处受压弯曲有的刀具受强烈振动、冲击时崩落一块(即崩刃)有的小型刃具整体折断等等。但这些情况毕竟比较少见，刃具较普遍的失效形式是磨损，当刃具磨削到一定程度后就不能正常工作了(否则会影响加工质量。
由上述可知(刃具钢应具有如下使用性能
(1)为了保证刀刃能犁人工件并防止卷刃必须使刃具具有高于被切削材料的硬度(一般应在HRC60以上，加工软材料时可为HRC45,55)故刃具钢应是以高碳马氏体为基体的组织。
(2)为了保证刃具的使用寿命(应当要求有足够的耐磨性。高的耐磨性不仅决定于高便度，同时也决定于钢的组织。在马氏体基体上分布着弥散的碳化物(尤其是各种合金碳化物能有效地提高刃具钢的耐磨损能力
(3)由于在各种形式的切削加工过程中(对具承受着冲击、振动等作用，应当要求对具有足够的塑性和韧性(以防止使用中崩刃或折断。
(4)为了使刃具能承受切削热的作用(防止在使用过程中因温度升高而导致硬度下降(应要求刃具有高的红硬性。钢的红硬性是指钢在受热条件下(仍能保持足够高的硬度和切削能力，这种性能称为钢的红硬性。红硬性可以用多次高温回火后在室温条件下测得的硬度值来表示。所以air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
红硬性是钢抵抗多次高温回火软化的能力，实质上这是一个
回火抗力的问题。
应当指出(上述四点是对刃具钢的一般使用性能要求(而视使用条件的不同可以有所侧重。如挫刀不一定需要很高的红硬性(而钻头工作时(其对部热量散失困难(所以对红硬性要求很高。
此外，选择刃具钢时(应当考虑工艺性能的要求(例如(切削加工与磨削性能好(具有良好的淬透性(较小的淬火变形、开裂敏感性等各项要求都是刀具钢合金化及其选材的基本依据。 二、刃具钢的钢种衍变
通常按照使用情况及相应的性能要求不同(将刃具钢分为:碳素工具钢、合金工具钢和高速钢三类。衡量一个国家工具材料的水平常以高速钢为标准(故重点讨论之。
1.碳素刃具钢
由二所述(刃具钢最基本的性能要求是;高硬度高耐磨性。高硬度是保证进行切削的基本条件，高耐磨性可保证刃具有一定的寿命(即耐用度。针对上述两个要求(最先发展起来的是碳素刃具钢。其合碳量范围在0.65%,1(35,，属高碳钢(包括亚共析钢、共析钢和过共析钢。
碳素刃具钢的热处理工艺为淬火十低温回火。一般亚共析钢采用完全淬火(淬火后的组织为细针状马氏体。过共析钢采用不完全淬火(淬火后的组织为隐晶马氏体十位溶碳化物(且由于未溶碳化物的存在，使钢的韧性较低(脆性较大(所以在使用中脆断倾向性大(应予以充分注意。
在碳素刃具钢正常淬火组织中还不可避免地会有数量不等的残余奥氏体存在。
常用的碳素对具钢的成分、性能和用途如表4.1所示。
碳素刃具钢在性能上有两个缺点、一个不足(即淬透性低(工具断面尺寸大于15mm时(水淬后只有工件表面层有高硬度(故不能做形状复杂、尺寸较大的刀具;红硬性差(当工作温度超过250?，硬度和耐磨性迅速下降(而失去正常工作的能力;碳素刃具钢从成分上看，不含有合金元素(淬火回火后碳化物属于渗碳体型(硬度虽然可达HRC62
但耐磨性不足。
碳素刃具钢在热处理时须注意以下几点?碳素工具钢淬透性低，为了淬火后获得马氏体组织(淬火时工件要在强烈的淬火介质(如水、盐水、碱水等)中冷却(因而淬火时产生的应力大(将引起较大的变形甚至开裂(故而淬火后应及时回火?碳素刃具钢在淬火前经球化退火处理，在退火处理过程中(由于加热时间长、冷却速度慢，会有石墨析出使钢脆化(称为黑脆)。?碳素刃具钢由于含碳量高(在加热过程中易氧化脱碳(所以加热时须注意保护(一般用盐浴炉或在保护气氛条件下加热。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
综上所述，由于碳素工具钢淬透性低、红硬性差、耐磨性不够高(所以只能用来制造切屑量小、切削速度较低的小型刃具(常用来加工硬度低的软金属或非金属材制。对于重负荷、尺寸较大、形状复杂工作温度超过200?的刃具(碳素刃具钢就满足不了工作的要求、在制造这类刃具时应采用合金刃具钢、但碳素刃具钢成本低，在生产中应尽量考虑选用。
表 碳素工具钢的牌号、成分和用途
化学成分(%) 硬度
供应状淬火后 牌号 用途举例 态 C Si Mn HRC(不大HB(不大于) 于)
T7 0.65,?承受冲击，任性较好，硬度适当的工具，如扁?0.40 187 62 T7A 0.75 0.35 铲、手钳、大锤、木工工具 T8 0.75,?承受冲击，任性较好，硬度适当的工具，如扁?0.40 187 62 T8A 0.84 0.35 铲、手钳、大锤、木工工具
承受冲击，任性较好，硬度适当的工具，如扁T8Mn 0.80,??0.40,187 62 铲、手钳、大锤、木工工具，但淬透性较大。T8MnA 0.90 0.35 0.60 可制断面较大的工具
T9 0.85,?韧性中等、硬度高的工具、如冲头、木工工具、?0.40 192 62 T9A 0.94 0.35 凿岩工具
T10 0.95,?不受剧烈冲击，高硬度耐磨的工具、如车刀、?0.40 187 62 T10A 1.04 0.35 刨刀、丝锥、钻头、手锯条 T11 1.05,?不受剧烈冲击，高硬度耐磨的工具、如车刀、?0.40 207 62 T11A 1.14 0.35 刨刀、丝锥、钻头、手锯条 T12 1.15,?不受剧烈冲击，高硬度耐磨的工具、如锉刀、?0.40 207 62 T12A 1.24 0.35 刮刀、丝锥、精车刀、量具
不受冲击，高硬度耐磨的工具、如锉刀、刮刀、T13 1.25,??0.40 217 62 丝锥、精车刀、量具要求更高耐磨的工具如刮T13A 1.35 0.35 刀、锉刀。
?淬火后硬度不是指用途举例中各种工具的硬度，而是指碳素工具钢材料在淬火后的最低硬度。 2.合金刃具钢
合金刃具钢是在碳素刃具钢的基础上加入某些合金元素而发展起来的。其目的是克服碳素刃具钢的淬透性低、红硬性差、耐磨性不足的缺点。合金刃具钢的合碳量在0.75,,1.5,合金元素总量则在5,以下(所以又称低合金刃具钢。加入的合金元素为Cr、Mn、Si、W和V等。其中Cr、Mn、Si主要是提高钢的淬造性(同时强化马氏体基体，提高h回火稳定性;W和V还可以细化晶粒; Cr、 Mn等可溶入渗碳体(形成合金渗碳体，有利于钢耐磨性的提高。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
另外，Si使钢在加热时易脱碳和石墨化(使用中应注意。如 Si、 Cr同时入钢中则能降低钢的脱碳和石墨化倾向。
合金刃具钢有如下特点;淬透性较碳素刃具钢好，淬火冷却可在油中进行，放热处理变形和开裂倾向小，耐磨性和红硬性也有所提高。但合金元素的加入，提高了钢的临界点，故一般淬火温度较高(使脱碳倾向增大。
合金刃具钢主要用于制作:?截面尺寸较大且形状复杂的刃具:?精密的刀具;?切削刃在心部的刃具，此时要求钢的组织均匀性要好:?切削速度较大的刃具等。
我国冶标YB 7—59列入了56种合金刃具钢。表4(2列出了最常用的合金刀具钢的成分、热处理工艺、性能和用途。
表 常用合金刃具钢的牌号、成分和热处理规范
由表可见(合金刀具钢分为两个体系
针对提高钢的淬透性的要求，发展了Cr、Cr2、9SiCr和CrWMn等钢。其中9SiCr钢在抽中淬火淬造直径可达40—50 mm(适宜制造薄刃或切削刀在心部的工具(如板牙、滚丝轮、丝 锥等。
CrWMn钢是最常用的合金刃具钢。经热处理后硬度可达HRC64—66且有较高的耐磨性。CrWMn钢淬火后(有较多的残余奥氏体，使其淬火变形小(故有低变形钢之称。生产中常用调整淬火温度和冷却介质配合，使形状复杂的薄壁工具达到激变形或不变形。这种钢适于做截面尺寸较大、要求耐磨性高、淬火变形小(但工作温度不高的拉 刀、长丝锥等。也可作量具、冷变形模具和高压油泵的精密部件(柱塞)等。
针对提高耐磨性的要求，发展了Cr06、W、W2及CrW5等钢。其中CrW5又称钻石钢(在水中冷却时，硬度可达HRC67—68。主要用于制作截面尺寸不大(5,15mm)、形状简单又要求高硬度、高耐磨性的工具，如雕刻工具及切削硬材料的刃具。
合金刃具钢的热处理与碳素刃具钢基本相同，也包括加工前的球化退火和成形后的淬火与低温回火(回火温度一般为160—200?。合金刃具钢为过共析钢一般采用不完全淬火。淬火加热温度要根据工件形状、尺寸及性能要求等选定并严格控制(以保证工件质量。另外(合金刃具钢导热性较差(对于形状复杂、截面尺寸大的工件，在淬火加热前往往先在600—650?左右进行预热，然后再淬火加认一般采用油淬、分级淬火或等温淬火。少数淬透性较低的钢(如Cr06(CrW5等钢)采用水淬。
综上所述(合金刃具钢解决了淬透性低、耐磨性不足等缺点。但由于合金刃具钢所加合金元素数量不多(仍属于低合金范围(故其红硬性虽比碳素刃具钢高(但仍满足不了生产要求。如回air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
火温度达到250?时硬度值已降到HRC60以下。因此要想大幅度提高钢的红硬性，靠合金刃具钢难以解决，故发展了高速钢。
3.高速钢
多少年来(人们为了提高切削速度(除了改善机床和刀具设计外(刀具材料一直是一个核心问题。前已指出合金刃具钢基本上解决了碳素刀具钢淬透性低、耐磨性不足的缺点，但没有从根本上解决红硬性不高的问题。只有在高速钢问世以后，不但保证了钢的淬透性和耐磨性，而且红硬性也得到了显著提高。
高速钢是一种高碳且含有大量W、Mo、Cr、V、Co等合金元素的合金刃具钢。
高速钢经热处理后，在600?以下仍然保持高的硬度(可达HRC60以上故可在较高温度条件下保持高速切削能力和高耐磨性。同时具有足够高的强度，并兼有适当的塑性和韧性，这是其他超硬工具材料所无法比拟的。高速钢还具有很高的淬透性(中小型刃具甚至在空气中冷却也能淬透，故有风钢之称。
同碳素刃具钢和合金刀具钢相比，高速钢的切削速度可提高2,4倍，刃具寿命提高8—15倍。
高速钢广泛用于制造尺寸大、切削速度快、负荷重及工作温度高的各种机加工工具。如车刀、刨刀、拉刀、钻头等。此外(还可应用在模具及一些特殊轴承方面。总之(现代工具材料高速打仍占对具材料总量的65,而产值则占70,左右(所以高速钢自问世以来(经百年使用而不衰。
(l)高速钢的化学成分。高速钢是含有大量W、Mo、Cr、V及Co的高碳高合金钢。高速钢成分大致范围如下C0.7,一1.65,、W0,一12,、Mo0,,10,、约Cr4%、V1,,5,及Co0%,12%%5，高速钢中也往往含有其它合金元素如Al、Nb、Ti、Si及稀土元素、总量小于2,。
?碳的作用。碳在淬火加热时溶入基体a相中，提高了基作中碳的浓度，这样既可提高钢的淬透性，又可获得高碳马氏体，进而提高了硬度。高速钢中碳与合金元素Cr、W、Mo、V等形成合金碳化物，可以提高硬度、耐磨性和红硬化高速钢中合碳量必须与合金元素相匹配，过高过低都对其性能有不利影响(每种钢号的合碳量都限定在较窄的范围。所以有人提出平衡碳理论，认为高速钢中含磷量应该满足下式
C=0.033W十0.063Mo+0.060Cr+0.200V
此式称为G(steven的平衡碳计算式。式中化学符号代表1,100含量，如W1,(质量)要求有0.033,的碳与之相匹配(V1,(质量)要求有)2,的碳相匹配(以下如此类推。
?合金元素的作用。高速钢的合金代主要是围绕提高红硬性这,中心环节而展开的。加入会金元素Cr、W、Mo、V等(以形成大量细小、弥散、坚硬而又不易聚集长大的合金碳化物(以造air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
成二次硬化效应。通常所形成的强化相有MC型(如WC、MoC)、 MC型碳化物(如 VC)、 MC222236型碳化物(如 CrC)等。这些碳化物硬度很高(如 VC的硬度可高达 HV2700,2990，并且在高236
温下不易发生聚集长大。另外、W的存在可提高马氏体的高温稳定优W系高速钢在450,60?还能保持马氏体晶格特征，以维持高的硬度。同时也使w的碳化物在560?仍保持极为细小的尺寸(于是提供了二次硬化的能力。
由于对具进行高速切削时，使用温度大体在500—600?还以上，故高速钢实际上是一种热强钢，即高速钢基体有一定的热强性，而合金元素Cr、W、Mo在高温下固溶强化效果显著，使基体有一定的热强性。这便是高速钢含有大量的Cr、W、Mo等合金元素的目的。
此外，也应指出，Cr的良好作用在于提高钢的淬透性与耐磨性。Cr还能使高速钢在切削过程中的抗氧化作用增强(形成较多致密的氧化股(并减少粘刀现象，从而使刃具的耐磨性与切削性能提高。
有些高速钢中加Co元素可显著提高钢的红硬性，如W2Mo10Cr4Co8〔美国M42)钢在650,660?时还具有很高的红硬性。Co虽然不是碳化物形成无氟但在退火状态下大部分Co处于a-Fe中(在碳化物MoC中仍有一定的溶解度;
可提高高速钢的熔点，从而使淬火温度提高，使奥氏体中溶解更多的W、 Mo、V等合金元素，可强化基体;Co可促进
回火对合金碳化物的析比还可以起减慢碳化物长大的作用(因此Co可通过细化碳化物而使钢的二次硬化能力和红硬性提高;Co本身可形成CoW金属间化合物，产生弥散强化效果，并能阻止其它碳化物聚集长大。
图中表示了不同含铅量对高速钢切削寿命、
硬度及红硬性的影响。
综上所述(由于高速钢的成分特点(便决定
了高速钢在一定的热处理工艺条件下，具有淬透
性好、耐磨性及红硬性高的性能特点
(2)高速钢的铸态组织及其压力加工。高速
钢在成分上差异较大，但主要合金元素大体相同、
所以其组织也很相似。以W18Cr4V钢为例，当钢
成接近平衡冷却时。其在室温下的平衡组织为荣氏体十珠光体十碳化物。但在实际生产中，高速钢铸件冷却速度较快(得不到上述平衡组织，这样(高速钢的铸态组织由鱼骨状菜氏体、黑色组织δ共析体及马氏体加残余奥氏体所组成。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
高速钢的铸态组织中出现莱氏体(故又称高速钢为莱氏体钢。
高速钢铸态组织中的碳化物含量多达18,一27,，且分布极不均匀。虽然铸锭组织经过开还和轧制，但碳化物的不均匀性仍非常显著。这种不均匀性对钢的力学性能和工艺性能及所制工具的使用寿命均有很大影响。
(3)高速钢的热处理。
高速钢的热处理包括:机械加工前的球化退火处理和成形后的淬火回火处理。
?高速钢球化退火。高速钢锻造以后必须经过球化退火(其目的不仅在于降低钢的硬度，以利于切削加工(而且也为以后的淬火做好组织准备。另外，返修工件在第二次淬火前也要进行球化退火(否则，第二次淬火加热时，晶粒将过分长大而使工件变脆。
?高速钢淬火。高速钢的热处理工艺曲线如图所示。高速钢的淬火工艺比较特殊:即经过两次预热、高温淬火，然后再进行三次高温回火。
高速钢淬火时进行两次预热(其原因在于:?高速钢中含有大量合金元素(导热性较差、如果把冷的工件直接放人高温炉中(会引起工件变形或开裂，特别是对大型复杂工件则更为突出。?高速钢淬火加热温度大多数在1200?以上，如果先预热(可缩短在高温处理停留的时间，这样可减少氧化脱碳及过热的危险性。
高速钢第一次预热温度在600,650?可烘干工件上的水分。第二次预热温度在800,820?，使索氏体向奥氏体的转变可在较低温度内发生。
高速钢中含有大量难溶的合金碳化物，淬火加热温度必须足够高才可使合金碳化物溶解到奥氏体中(淬火之后马氏体中的合金元素含量才足够高(而只有合金元素含量高的马氏体才具有高的红硬性。图中已经表示出了淬火温度对奥氏体(或马氏体)内合金元素含量的影响、由此可知，对高速钢红硬性影响最大的合金元素是W、Mo及V只有在1000?以上时(其溶解量才急剧增加。温度超过1300?时，各元素溶解量虽然还有增加，但奥氏体晶粒则急剧长大(甚至在晶界处发生熔化现象，致使钢的强度、韧性下降。所以在下发生过热的前提下，高速钢淬火温度越高(其红硬性越民在生产中常以淬火状态奥氏体晶粒的大小来判断淬火加热温度是否合适(对高速钢来说(合适的晶粒度为9.5,10.5级。
淬火冷却通常在油中进行(但对形状复杂、细长杆状或薄片零件可采用分级淬火和等温淬火等方法。分级淬火后使残余奥氏体量增加20,,30,，使工件变形、开裂倾向减小，使强度、韧性提高。油淬及分级淬火后的组织为马氏体十碳化物十残余奥氏体。如图所示。
等温淬火也称奥氏体淬火(也有人称之为无变形淬火。等温淬火和分级淬火相比(其主要淬air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
火组织中除马氏体，碳化物、残余奥氏体外，还有了下贝氏体。等温淬火可进一步减小工件变形，并提高韧性。
最后应提出，分级淬火的分级温度停留时间一般不宜太长，否则二次碳化物可能大量析出。等温淬火所需时间较长(随等温时间不同，所获得贝氏作量不同，在生产中通常只能获得40,的回氏体。而等温时间过长可大大增加残余奥氏体量(这需要在等温淬火后进行冷处理或采用多次回火来消除残余奥氏体。否则将会影响回火后的硬度及热
处理质量。
?高速钢回火。为了消除淬火应力、稳定组织、减少残余奥氏体量、达到所需要的性能(高速钢一般要进行三次560?的高温回火处理。高速钢的回火转变比较复杂(在回火过程中马氏体和残余奥氏体发生变化，过剩碳化物在回火时不发生变化。
综上所述，高速钢在热处理操作时(必须严格控制淬火加热及回火温度，淬火、回火保温时间，淬火、回火冷却方法。上述工艺参数控制不当，易产生过热、过烧、萘状断口、硬度不足及变形开裂等缺陷(
(4)高速钢系列的演变。目前国内外高速钢的种类约有数十种，按其所含含金元素的不同(可分为三个基本系列(即W系Mo系和W-Mo系等。W系高速钢以W18Cr4V为例(W18Cr4V钢具有很高的打硬性(可以制造在600?以下工作的工具但在使用中发现W系高速钢的脆性较大，易于产生崩刃现象，其主要原因是碳化物不均匀性较大所致、为此(相应发展了Mo系高速钢。从保证红硬性角度看，Mo与W的作用相认(Mo系高速钢是以Mo为主要合金元素(常用钢种有M1和M10(W2Mo8Cr4V和Mo8Cr4V2)。Mo系高速钢具有碳化物不均匀性小和韧性较高的优成但又存在两大缺点(限制了它的应用一是脱碳倾向性较大(故对热处理保护要求较严:二是晶粒长大倾向性较大(易于过热，故应严格控制淬火加热温度，淬火加热温度为 1175,1220?(W系高速钢淬火温度为1250,1280?)。
自50年代以来，又发展了特殊用途的高速钢(包括
?高钒高速钢。高钒高速钢主要是为适应提高耐磨性的需要而发展起来的(最早形成9Cr4V2钢、为了进一步提高钢的红硬性和耐磨性而形成了高碳高钒高速钢，如W12Cr4V4Mo及W6Mo5Cr4V3。增加V含量会降低钢的可磨削性能使高钒钢应用受到一定限制。
通常含V约3%的钢(尚可允许制造较复杂的刃具(而含V量为4,,5%时(则宜制造形状简单或磨削量小的刃具。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
?高钴高速钢。含Co高速钢是为适应提高红硬性的需要而发展起来的。
在高 Co高速钢中通常含有 Co5,, 12%，如 W7Mo4Cr4V2Co5、W2Mo9Cr4VCo8等。但随着含Co量的增加(会使钢的脆性及脱碳倾向性增大(故在使用及热处理时应予以注意(例如含Co10,的钢已不适宜于制造形状复杂的薄刃工具。
?超硬高速钢.超硬高速钢是为了适应加工难切削材料(如耐热合金等)的需要，在综合高碳高钒高速钢与高碳高钴高速钢优点的基础上而发展起来的。这种钢经过热处理后硬度可达HRC68,70，具有很高的红硬性与切屑性能。典型钢种为美国的M42(W2Mol0Cr4VCo8)和M44(W6Mo5Cr4V2Co12)等。
(5)发挥高速钢性能潜力的途径:
?提高含碳量。近年来，世界各国都普通趋向提高高速钢的含碳量，其目的是增加钢中碳化物的含量(以获得最大的二次硬化效应。但含碳量过高会增加碳化物的不均匀性(使钢的塑性、韧性下降(还会导致钢的熔点降低(碳化物聚集长大倾向性增大这对钢的组织和性能不利。自70年代以来，人们提出用平衡碳理论(前面已讲过)来计算高速钢的最佳含碳量。
例如，W18Cr4V钢含碳量为0.7,,0.8%按平衡假理论计算，其合碳量应提高至0.9,,1.0%，淬火回火后其硬度才可达HRC67,68， 625?回火时其红硬性提高三个HRC读数。
?进一步细化碳化物。前已指出，细化碳化物可提高动性、防止崩刃，是充分发挥高速钢性能潜力的重要方法。除了在生产中采用锻、轧方法外(还可采用以下措施(一是改进冶炼、浇注工艺(以减少碳化物的偏析，如生产上采用电渣重溶可以显著细化菜氏体共晶组织(改善钢中碳化物的不均匀性。在浇注工艺上宜采用200一300kg的小锭(使钢液凝固速度加快，以减少钢锭中的宏观液析。二是采用粉末冶金方法，从根本上消除菜氏体共晶组织(以彻底解决高速钢中碳化物的不均匀性。采用这种方法可以得到极为细小的碳化物(, 1um)，而且分布均匀。与普通方法生产的高速钢相比(这种方法可提高钢的韧性与红硬性。但粉末冶金生产高速钢的主要缺点是(成本高，质量
不稳定。
?表面处理工艺的应用。为了进一步提高高速钢的切削能力在淬火回火后还可进行表面处理。例如，蒸汽处理、低温氰化、软氮化、硫氮共渗或采用硫氛共修一蒸汽处理的复合工艺等。如哈尔滨一工具厂采用蒸汽处理后可使钻头寿命提高20,左右。
应该指出，高速钢的表面处理是在最终热处理后进行的(故表面处理的温度不应超过回火温度，以免使刀具软化。同时因刃具已成形，故应防止刃具发生变几间)高速钢的发展方向。在air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
国外，通过研究已探索出新的合主化方案(当前已在生产中形成初见成效的两个方向;
?低碳高速钢(M60,67)。这种钢是采用含Co超硬高速钢的合金成分(将碳量降至0.2,左右，通过渗碳及随后的淬火、回火(使表层达到超高硬度(HRC70)故又称渗碳高速钢。
?无碳的时效型高速钢。这种钢是在高w高Mo的基础上(加入15%以上的Co(甚至可高达25,的Co，经固溶处理加时效以后(硬度可达HRC68,70，它的红硬性比一般高速钢高100?、比含Co的超硬型高速钢高50?以上。经L述处理后可使工具的切削性能、高温强度及耐磨性发生重大变化。
1975年在法国的国际高速钢会议上有人提出，含有低碳(约0.1,)高W(约20,)高钴(25,)的高速钢(在600一650?回火时(拆出(Fe、Co)W型金属问他合物。当温度上升到76
650,670?时，其硬度可达HRC68，在720?回火时，硬度仍保持HRC60。
此类型的高速钢切削钛合金时(其寿命比W18Cr14V高出20,30倍。
对于目前正在使用的各种高速钢(仍需进一步研究各种合金元空(包括残余元素和微量合金元素)的作用，以便进一步提高其使用性能和工艺性能。
最后应指出，目前高速钢的使用范围已经超出了切削工具范围(已开始在模具方面应用。近年来多辊轧辊以及高温弹簧、高温轴承和以高温强度、耐磨性能为主要要求的零件，实际上都是高速钢可以发挥作用的领域。
16(3模具用钢
模具是机械制造、无线电仪表、电机电器等工业部门中制造零件的主要加工工具。模具的质量直接影响着压力加工工艺的质量、产品的精度产量和生产成本、而模具的质量与使用寿命除了靠合理的结构设计和加工精度外，主要受模具材料和热处理的影响。因此，为了正确选用钢材，制订和改进热处理工艺，提高模具的使用寿命，必须对模具的工作条件、失效形式及其对钢材的性能要求进行综合分析，寻找失效的主要固氮以确定材料的种类，进而确定最佳冷、热加工工艺和强化措施，从而做到材尽其用。
模具钢是用来制造冷冲模、热锻模压铸模等模具的钢种其品种繁多(在我国国标中多达数十种。但是(根据模具的使用性质可以分为两大类;使金属在冷状态下变形的冷模具钢(其冷模的工作温度一般小于250?使金属在热状态下变形的热模具钢(其模腔的表面温度高于600?。 一、冷作模具钢
冷作模具钢包括制造冲截用的模具(落料冲孔模、修边模、冲头、剪刀)、冷镦模和冷挤压模、压弯模及拉丝模等
1.冷作模具钢的工作条件及性能要求
冷作模具钢在工作时(由于被加工材料的变形抗力比较大，模具的工作部分承受很大的压力、弯曲力、冲击力及摩擦力。因此，冷作模具的正常报废原因一般是磨损(也有因断裂、崩力和变形超差而提前失效的。
冷作模具钢与刃具钢相比(有许多共同点。要求模具有高的硬度和耐磨性、高的抗弯强度和足够的韧性，以保证冲压过程的顺利进行、其不同之处在于模具形状及加I工艺复杂(而且摩擦air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
面积大(磨损可能性大(所以修磨起来困难。因此要求具有更高的耐磨化模具工作时承受冲压力大(又由于形状复杂易于产生应力集中，所以要求具有较高的韧性;模具尺寸大、形状复杂(所以要求较高的淬透性、较小的变形及开裂倾向性。总之，冷作模具钢在淬透性、耐磨性与韧性等方面的要求要较刃具钢高一些(而在红硬性方面却要求较低或基本上没要求(因为是冷态成形)，所以也相应形成了一些适于做冷作模具用的钢种，例如，发展了高耐磨、微变形冷作模具用钢及高韧性冷作模具用钢等。下面结合有关钢种选用进一步说明。
2.钢种选择
通常接冷作模具的使用条件，可以将钢种选择分为以下四种情况:
(1)尺寸小、形状简单、轻负荷的冷作模具。例如(小冲头，剪落钢板的剪刀等可选用T7A、 T8A、T10A、T12A等碳素工具钢制造。这类钢的优点是;可加工性好、价格便宜、来源容易。但其缺点是:淬透性低、耐磨性差、淬火变形大。因此，只适于制造一些尺寸小、形状简单、轻负荷的工具以及要求硬化层不深并保持高韧性的冷像模等。
(2)尺寸大、形状复杂、轻负荷的冷作模具。常用的钢种有9SiCr、CrWMn、GCr15及 9Mn2V等低合金刃具钢。这些钢在油中的淬透直径大体上可达40mm以上。其中9Mn2V钢是我国近年来发展的一种不含Cr的冷作模具用钢(可代替或部分代替含Cr的钢。
9Mn2V钢的碳化物不均匀性和淬火开裂倾向性比CrWMn钢小、脱碳倾向性比9SiCr钢小，而淬透性比碳素工具钢大(其价格只比后者高约30,因此是一个值得推广使用的钢种。
但9Mn2V钢也存在一些缺点如冲击韧性不高，在生产使用中发现有碎裂现象(另外回火稳定性较差，回火温度一般不超过180?在200?回火时抗弯强度及韧性开始出现低值。
9Mn2V钢可在硝盐、热油等冷却能力较为缓和的淬火介质中淬火。对于一些变形要求严格而硬度要求又不很高的模具，可采用奥氏体等温淬火。
(3)尺寸大、形状复杂重负荷的冷作模具。须采用中合金或高合金钢(如Cr12Mo、 Crl2MoV、 Cr6WV Cr4W2MoV等，另外也有选用高速钢的。
近年来用高速钢做冷作模具的倾向巴日趋增大、但应指出，此时已不再是利用高速钢所特有的红硬性长处(而用它的高淬透性和高耐磨性。为此(在热处理工艺上也应有所区别。
选用高速钢做冷模具时(应采用低温淬火(以提高韧性。例如 W18Cr4V钢做刃具时常用的淬火温度为1280-1290?。而做冷作模具时，则应采用1190?的低温淬火。又如 W6Mo5Cr4V2钢(采用低温淬火后可使寿命大大提高、特别是显著减少了折损率。
〔4)受冲击负荷且刀间单薄的冷作模具。如上所述(前三类冷作模具用钢的使用性能要求均以高耐磨性为主为此均采用高碳过共析钢乃至荣氏体钢。而对有的冷作模具加切边楼、冲裁模等(其对口单薄(使用时又受冲击负荷作用则应以要求高的冲击韧性为主。为了解决这一矛盾(可采取以下措施(?降低合碳量(采用亚共折钢(以避免由于一次及二次碳化物而引起钢的韧性下降;?加入Si(、Cr等合金元素(以提高钢的回火稳定性和回火温度(240一270?回火)这样有利于充分消除淬火应力使叽提高(而又不致降低硬度;?加入W等形成难熔碳化物的元素以细化晶粒、提高韧性。常用的高韧性冷作模具用钢有6SiCr、4CrW2Si;、5CrW2Si等。
3.充分发挥冷作模具钢性能潜力的途径
在用Cr12型钢或高速钢做冷作模具时，一个很突出的问题是钢的脆性大(使用中易开裂。为此，必须用充分锻打的方法细化碳化物(除此之外应发展新钢种。发展新钢种的着眼点，应是降低钢的含碳量及碳化物形成元素的数量。近年来国内研制并推广以下几种新钢种、如表4.11所示。
Cr4W2MoV 钢具有高硬巨、高耐磨性和淬透性好等优点(并具有较好的回火稳定性及综合力学性能(用干制造硅钢片冲模等(可使寿命比Cr12MoV钢提高1,3倍以上但此钢锻造温区范围较窄，锻造河县开裂(应严格控制锻造温度和操作规认Cr2Mn2SiWMoV钢淬火温度低、淬火变形小、淬透性高(有空淬微变形模具钢之称7W7Cr4MoV钢可代W18Cr4V和Cr12MoV钢(其特点是钢air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
的碳化物不均匀性和韧性得到很大的改善。
二、热作模具钢
1.热作模具的工作条件
热作模具包括锤锻模、热挤压模和压铸模三类。如前所述(热作模具工作条件的主要特点是与热态金属相接触、这是与冷作模具工作条件的主要区别。因此会带来以下两方面的问题:
(l)模腔表层金属受热。通常锤锻模工作时(其模腔表面温度可达300,400?以上热挤压
?以上;压铸模模腔温度与压铸材料种类及浇注温度有关。如压铸黑色金属时模可达500一800
模腔温度可达1000?以上。这样高的使用温度会使模腔表面硬度和强度显著降低，在使用中易发生打垛。为此(对热模具钢的基本使用性能要求是热塑变抗力高，包括高温硬度和高温强度、高的热塑变抗力，实际上反映了钢的高回火稳定性。由此便可以找到热模具钢合金化的第一种途径，即加入Cr、W、Si(等合金元素可以提高钢的回火稳定性。
(2)模腔表层金属产生热疲劳(龟裂)。热模的工作特点是具有间歇性(每次使热态金属成形后都要用水、油、空气等介质冷却模腔的表面。因此(热模的工作状态是反复受热和冷却，从而使模腔表层金属产生反复的热胀冷缩，即反复承受拉压应力作用(其结果引起模腔表面出现龟裂，称为热疲劳现象，由此，对热模具钢提出了第二个基本使用性能要求(即具有高的热疲劳抗力。一般说来，影响钢的热疲劳抗力的因素主要有:
?钢的导热性。钢的导热性高，可使模具表层金属受热程度降低，从而减小钢的热疲劳倾向性。一般认为钢的导热性与合碳量有关，含碳量高时导热性低，所以热作模具钢不宜采用高碳钢。在生产中通常采用中碳钢(C0.3%5,0.6%)合碳量过低(会导致钢的硬度和强度下降(也是不利的。
?钢的临界点影响。通常钢的临界点(A)越高(钢的热疲劳倾向性越低。因此(一般通过cl
加入合金元素Cr、W、Si、引来提高钢的临界点。从而提高钢的热疲劳抗力。
2.常用热作模具用钢
(1)锤锻模用钢。一般说来，锤锻模用钢有两个问题比较突出一是工作时受冲击负荷作用(故对钢的力学性能要求较高，特别是对塑变抗力及韧性要求较高;二是锤锻模的截面尺寸较大(,400mm)故对钢的淬透性要求较高，以保证整个模具组织和性能均匀。
常用锤锻楼用钢有5CrNiMo、 5CrMnMo、 5CrNiW、 5CrNiTi及5CrMnMoSiV等。不同类型的锤眼模应选用不同的材料。对特大型或大型的锤锻模以5CrNiMo为好(也可采用5CrNiTi、5CrNiW或5CrMnMoSi等。对中小型的锤锻模通常选用5CrMnMO钢。
(2)热挤压模用钢，热挤压模的工作特点是加载速度较慢，因此，模腔受热温度较高，通常可达500一800?。对这类钢的使用性能要求应以高的高温强度(即高的回火稳定性)和高的耐热疲劳性能为主。对a及淬透性的要求可适当放低。一般的热挤压模尺寸较小，常小于 70,k
90 mm。
常用的热挤压模有4CrW2Si、3Cr2W8V及5,Cr型等热作模具钢(其化学成分如表4.16所示。
其中4CrW2Si(既可做冷作模具钢，又可做热作模具钢(由于用途不同，可采用不同热处理方法。作冷模时采用较低的淬火温度(870—900?)及低温或中温回火处理;作热模时则采用较高的淬火温度(一般为950一1000?)及高温回火处理。
(3)压铸模用钢。从总体上看，压铸模用钢的使用性能要求与热挤压模用钢相近，即以要求高的回火稳定性与高的热疲劳抗力为主。所以通常所选用的钢种大体上与热挤模用钢相同(如常采用4CrW2Si(和3Cr2W8V等钢。但又有所不同如对熔点较低Zn合金压铸模(可选用40Cr、30CrMnSi及40CrMo等;对Al和Mg合金压铸模，可选用4CrW2Si、4Cr5MoSiV 等对Cu合金压铸模(多采用3Cr2W8V钢。
近年来(随着黑色金属压铸工艺的应用，多采用高熔点的铝合金和镍合金(或者对3Cr2W8V钢进行Cr-Al-SI三元共渗，用以制造黑色金属压铸模。最近国内外还正在试验采用高强度的铜air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
合金作黑色金属的压铸模材料。
三、塑料模具用钢
目前塑料制品的应用日益广泛(尤其是在日常生活用品、电子仪表、电器等行业中应用十分广泛(已向塑料制品化方向发展。塑料制品大多采用模压成型，因而需要模具。模具的结构形式和质量对塑料制品的质量和生产效率有直接影响。
压制塑料有两种类型(即热塑性塑料和热固性塑料。热固性塑料如胶木粉等(都是在加热、加压下进行压制并永久成形的(胶木模周期地承受压力并在150,200?温度下持续受热。热塑性塑料加聚氯乙烯等，通常采用注射模塑法，塑料是在单独的加热空加热，然后以软化状态注射到较冷的塑模中，施加压力，从而使之冷硬成形。注射模的工作温度为120一260?，工作时通水冷却型腔，故受热、受力及受磨损程度较轻。值得注意的是含有氯、氟的塑料(在压制时析出有害的气体，对模腔有较大的侵蚀作用。
综上所述(对塑料模具提出如下要求:?钢料纯净(要求夹杂物少、偏析少，表面光洁度高;?表面耐磨抗蚀，并要求有一定的表面硬化层，表面硬一般在HRC45以上:?足够的强度和韧性:?热处理变形小(以保证互换性和配合精度。塑料模具的制造成本高材料费用只占模具成本的极小部分，因此选用钢材时(应优先选用工艺性能好性能稳定和使用寿命较长的钢种。塑料模具用钢可分以下几类;
?适于冷挤压成形的塑料模用钢是工业纯铁和10、15， 20、20Cr钢。其加工工艺路线:锻造-退火-粗加工-冷挤压成形-高温回火-加工成形-渗碳-淬火-回火-抛光-镀铬-装配。
?对于中小型、且不很复杂的模具(可用T7A、T10A、9Mn2V、CrWMn、Cr2钢等。对于大型塑料模具可采用4Cr5MoSiV或PDAHT-1钢C0.8,一0.9,、Mn1.8,,2(2%、?Si0.35,、Cr0.9,,
,、V0.1,一0.3,)在要求高耐磨性时也可采用Cr12MoV钢。其加工工1.1,、Mo1.2,一1.5
艺路线;锻造-退火-粗加工-调质或高温回火-精加工-淬火-回火-钳工抛光-镀铬-抛光装配。
?复杂、精密模具使用18CrMnTi 12CrNi3A和12Cr2Ni4A等渗碳钢(其加工工艺路线同上述?所示。
?压制会析出有害气体并与钢起强烈反应的塑料(可采用马氏体不锈钢2Cr13或3Cr13钢。模具加热温度在950一1000?油淬(并在200,220?回火。热处理后其HRC=45—50，这类模具不需要镀铬。
塑料模具在淬火加热时应注意保护，防止表面氧化脱碳。热处理后最好先镀铝(以防目腐蚀、防止粘附，这样既易于脱模(又可提高耐磨性。
四、表面硬化技术在模具钢中的应用
随着工业生产的发展，对产品质量的要求日益严格，因而对模具的要求越来越高，相应地对模具也提出了高精度、高硬度、高耐磨性和高耐蚀性的要求。一般的模具经淬火、回人处理后便可满足要求(但对上述要求的模具应在淬火、回火处理基础上采用表面硬化处理，其方法如下:
?氮化处理(气体氮化、软氮化、离子氮化等)渗金属(渗Cr、Ae(Si(、B、V等)及气相沉积等方法(皆可提高模具的寿命。
?水蒸气处理。在水蒸气中对金属进行加热(在金属表面上将生成FeO，处理温度在550?34
左右、通过水蒸气处理之后(金属表面的磨擦系数将大力降低。这种技术主要用于淬火、回火的高合金模具钢的表面处理中。
?电火花表面强化。电火花表面强化是提高模具寿命的一种有效方法。它是利用火花放电时释放的能量(将一种导电材料溶渗到工件表面，构成合金化表面强化层(从而起到改善表面的物理化学性能的目的。
该工艺有如下特点电火花强化层是电极与工件材料的合金展强化层与基体结合牢固、耐冲击不剥落;强化处理时(工件处于冷态区放电点极小、时间短、不退火，不变形等。模具经电火花强化后(将大大提高模具表面的耐热性、耐蚀性、坚硬性和耐磨性，可获得较好的经济效果。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
模具一定要在淬火、回火处理后再进行强化处处理;操作要细心，电极沿被强化表面的移动速区要均匀、要控制好时间:模具经电火花强化处理后(表面产生残余拉应力，因此要补加一道低于回火温度30—50?的去应力处理。
例如，某厂冲不锈钢板落料模(原来一次刃磨寿命高 15000次，经电火花强化后(冲90000次未发现磨损(寿命提高 5倍。因此被广泛应用于模具、刃具及量具等工具。
?离子电镀的应用。离子电镀是1963年提出的(直到70年代才在工程上实现(并应用于工具和模具的表面硬化中。离子电镀具有如下特点:离子电镀时可以在500?以下温度进行(如果选择好处理方法和条件(可以在100?以下的温度进行;离子电镀与材料无关。可得到HV=2 000以上的硬化层;能得到各种金属和化合物的保护膜，且膜致密;无公害、无爆炸等危害。 16(4 量具用钢
一、量具的工作条件及量具用钢的性能要求
量具是用来度量工件尺寸的工具，如卡尺、块规、塞规及千分尺等。由于量具在使用过程中经常受到工件的磨擦与碰撞，而雨量具本身又必须具备非常高的尺寸精确性和恒定性(因此要求具有以下性能:
(1)高硬度和高耐磨性(以此保证在长期使用中不致被很快磨损，而失去其精度。
(2)高的尺寸稳定性(以保证量具在使用和存放过程中保持其形状和尺寸的恒定。
(3)足够的韧性(以保证量具在使用时不致因偶然因素——碰撞而损坏。
(4)在特殊环境下具有抗腐蚀性。
二、常用量具用钢
根据量具的种类及精度要求，量具可选用不同的钢种:
T12A。由于碳 (1)形状简单、精度要求不高的量具(可选用碳素工具钢(如T10A、TllA。素工具钢的淬透性低，尺寸大的量具采用水淬会引起较大的变形。因此(这类钢只能制造尺寸小、形状简单、精度要求较低的卡尺、样板、量规等量具。
(2)精度要求较高的量具(如块规、塞规料通常选用高碳低合金工具钢。如Cr2、CrMn、 CrWMn及轴承钢GCr15等。由于这类钢是在高碳钢中加入Cr、Mn、W等合金元素，故可以提高淬透性、减少淬火变形、提高钢的耐磨性和尺寸稳定性。
(3)对于形状简单、精度不高、使雨中易受冲击的量具，如简单平样板、卡规、直尺及大型量具，可采用渗碳钢15( 20、15Cr、20Cr等。但量具须经渗碳、淬火及低温回火后使用。经上述处理后(表面具有高硬度、高耐磨性、心部保持足够的韧性。也可采用中碳钢50、55 60、65制造量具(但须经调质处理(再经高频淬火回火后使用(亦可保证量具的精度。
(4)在腐蚀条件下工作的量具可选用不锈钢4Cr13、9Cr18制造(经淬火、回火处理后可使其硬度达HRC56—58，同时可保证量具具有良好的耐腐蚀性和足够的耐磨性。
若量具要求特别高的耐磨性和尺寸稳定性(可选渗氮钢38CrMoAl或冷作模具钢Cr12MoV。
3CrMoAl钢经调质处理后精加工成形，然后再氯化处理(最后需进行研磨。Cr12MoV钢经调质或淬火、回火后再进行表面渗氮或碳、氮共渗。两种钢经上过热处理后(可使量具具有高耐磨性、高抗蚀性和高尺寸稳定性。
三、量具钢的热处理
量具钢热处理的主要特点是在保持高硬度与高耐磨性的前提下，尽量采取各种措施使量具在长期使用中保持尺寸的稳定。量具在使用过程中随时间延长而发生尺寸变化的现象称为量具的时效效应。这是因为(?用于制造量具的过共析钢淬火后含有一定数量的残余奥氏体，残余奥氏体变为马氏体引起体积膨版。?马氏体在使用中继续分解，正方度降低引起体积收缩?残余内应力的存在和重新分布，使弹性变形部分地转变为塑性变形引起尺寸变化。因此在量具的热处理中(应针对上述原因采用如下热处理措施:
(1)调质处理。其目的是获得回火索氏体组织，以减少淬火变形和提高机械加工的光洁度。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(2)淬火和低温回火。量具钢为过共析钢(通常采用不完全淬火加低温回火处现在保证硬度的前提下，尽量降低淬火温度并进行预热，以减少加热和冷却过程中的温差及淬火应力。量具的淬火方式为油冷(20,30?)不宜采用分级淬火和等温淬火(只有在特殊情况下才予以考虑。一般采用低温回火，回火温度为150,160?，回火时间不应小于4,5h.
(3)冷处理。高精度量具在淬火后必须进行冷处理(以减少残余奥氏体量(从而增加尺寸稳定性。冷处理温度一般为一70—,80?并在淬火冷却到室温后立即进行，以免残余奥氏体发生陈化稳定。
(4)时效处理。为了进一步提高尺寸稳定性，淬火、回火后(再在120,150?进行24,36 h的时效处理，这样可消除残余内应力，大大增加尺寸稳定性而不降低其硬度。总之(量具钢的热处理为除了要进行一段过共析钢的正常热处理(不完全淬火十低温回火)之外(还需要有三个附加的热处理工序(即淬火之前进行调质处理、正常淬火处理之间的冷处理、正常热处理之后的时效处理。
第17章 不锈钢
17.1概述
不锈钢是石油、化工、化肥、合成纤维和石油提炼等工业部门中广泛使用的金属材和许多容器、管道、阀门、泵等一般都因与各种腐蚀性介质接触遭受腐蚀而报废。据统计，全世界每年因
4。而不锈钢的产量占钢铁总产量的1,。因此，材料受腐蚀而报废的钢材约占钢材年产量的1,
到腐蚀而失效是当今材料研究与发展中的三大主要问题之一(另两个问题是疲劳与磨损)。
不锈钢是指具有抗腐蚀性能的一类钢种。通常所说的不锈钢是不锈钢与耐酸钢的总称。不锈钢不一定耐酸，但耐酸钢同时又是不锈钢。所谓不锈钢是指能抵抗大气及弱腐蚀介质腐蚀的钢种。腐蚀速度,0(01 mm,年者分完全耐蚀腐蚀速度,0.1 mm,年者为耐蚀。所谓的耐酸钠是指在各种强腐蚀介质中能耐他的钢(腐蚀速度,0.1mm,年者为完全耐蚀，腐蚀速度,1mm,年者为耐蚀。因此(不锈钢并不是不腐蚀、只不过腐 蚀速度较慢而已、绝对不被腐蚀的钢是不存在的。
值得注意的是在同一介质中(不同种类的不锈钢腐蚀速度大不相同而同一种不锈钢在不同的介质中腐蚀行为也大不一样。例如(Ni-Cr不锈钢在氧化性介质中的耐蚀性很好(但在非氧化介质中(如盐酸)的耐蚀性就不好了。因此掌握各类不锈钢的特点、对于正确选择和使用不锈钢是很重要的。
不锈钢不仅要耐蚀，还要承受或传递载荷，因此还需要具有较好的力学性能。不锈钢一般以板、管等型材加工成构件或零件，因此(要有良好的切削加工性能和良好的焊接性能。
不锈钢按典型正火组织分为:铁素体(F)型不锈钢，马氏体〔M)型不锈钢、奥氏体(A)型不锈钢及奥氏体-铁素体(A-F)双相型不锈钢及沉淀硬化或过渡型)不锈钢。 17.2金属腐蚀
一、金属的腐蚀过程
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
在外界介质的作用下使金属逐渐受到破坏的现象称为腐蚀。腐蚀基本上有两种形式(化学腐蚀和电化学腐蚀。在生产实际中遇到的腐蚀主要是电化学腐蚀，化学腐蚀中不产生电流，巨在腐蚀过程中形成某种腐蚀产物。这种腐蚀产物一般都覆盖在金属表面上晒成一层膜 ，使金属与介质隔离开来。如果这层化学生成物是稳定、致密、完整并同金属表层牢固结合的，则将大大减轻甚至可以防止腐蚀的进一步发展，对金属起保护作用。形成保护膜的过程称为钝化。例如，生成SiOAlOCrO等氧化膜 ，这些氧化膜结构致密、完整、无疏松、无裂纹且不易剥落，可起到2、23、23
保护基体金属、避免继续氧化的作用。例如铁在高温氧化时生成的FeO。反之，有些氧化膜是23
不连续的 ，或者是多孔状的(对基体金属没有保护作用。例如(有些金属的氧化物，如MoO、23WO在高温下具有挥发性 ，完全没有覆盖基体的保护作用。 3
可见，氧化膜的产生及氧化膜的结构和性质是化学腐蚀的重要特征。因此，提高金属耐化学腐蚀的能力 ，主要是通过合金化或其它方法，在金属表面形成一层稳定的、完整阶致密的并与基体结合牢固的氧化膜(也称为钝化膜入电化学腐蚀是金属腐蚀的更重要、更普遍的形式它是由不同的金属或金属的不同朝之间的电极电位不同而构成原电池所产生的。这种原电池腐蚀是在显微组织之间产生的故又称之为微电池腐蚀。电化学腐蚀的特点是有电介质存在 ，不同金属之间、金属微区之间或相之间有电位差异连通或接触，同时有腐蚀电流产生。
二、腐蚀类型
金属材料在工业生产中的腐蚀失效形式是多种多样的。不同材料在不同负荷及不同介质环境的作用下，其腐蚀形式主要有以下几类 :
一般腐蚀:金属裸露表面发生大面积的较为均匀的腐蚀，虽降低构件受力有效面积及其使用寿命，但比局部腐蚀的危害性小。
晶间腐蚀:指沿品界进行的腐蚀，使晶粒的连接遭到破坏。这种腐蚀的危害性最大，它可以便会金变脆或丧失强度，敲击时失去金属声响，易造成突然事故。品同腐蚀为奥氏体不锈钢的主要腐蚀形式，这是由于品界区域与晶内成分或应力有差别 ，引起品界区域电极电位显著降低而造成的电极电位助差别所致。
应力腐蚀:金属在腐蚀介质及拉应力(外加应力或内应力)的共同作用下产生破裂现象。断裂方式主要是沿晶的、也有 穿晶的，这是一种危险的低应力脆性断裂、在氯化和碱性氛氧化物或其它水溶性介质中常发生应力腐蚀，在许多设备的事故中占相当大的比例。
点腐蚀:点腐蚀是发生在金属表面局部区域的一种腐蚀破坏形式、点腐蚀形成后能迅速地向深处发展，最后穿透金属。点腐蚀危害性很大庸 ，尤其是对各种容器是极为不利的。出现点腐蚀后应及时磨光或涂漆，以避免腐蚀加深。
点腐蚀产生的原因是在介质的作用下，金属表面钝化膜受到局部损坏而造成的。或者在含有氯离子的介质中，材料表面缺陷疏松及非金属夹杂物等都可引起点腐蚀。
腐蚀疲劳:金属在腐蚀介质及交变应力作用下发生的破坏、其特点是产生腐蚀坑和大量裂纹。显著降低钢的疲劳强度，导致过早断裂。腐蚀疲劳不同于机械疲劳，它没有一定的疲劳极限 ，随着循环次数的增加，疲劳强度一直是下降的。
除了上述各种腐蚀形式以外，还有由于宏观电池作用而产生的腐蚀。例如，金属构件中铆钉与铆接材料不同、异种金属的焊接、船体与螺旋桨材料不同等因电极电位差别而造成的腐蚀。
从上述腐蚀机理可见，防止腐蚀的着眼点应放在:尽可能减少原电池数量，使钢的表面形成air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
一层稳定的、完整的、与钢的基体结合牢固的钝化膜;在形成原电池的情况下 ，尽可能减少两极间的电极电位差。
17.3不锈钢的合金化原理
提高钢耐蚀性的方法很多，如表面镇一层耐蚀金属、涂敷非金属层、电化学保护和改变腐蚀环境介质等。但是利用合金化方法 ，提高材料本身的耐蚀性是最有效的防止腐蚀破坏的措施之一，其方法如下;
(1)加入合金元素，提高钢基体的电极电位，从而提高钢的抗电化学腐蚀能力。一般住钢中加入Cr、Ni、Si多元素均能提高其电极电位。由于Ni较缺，Si的大量加入会使钢变脆，因此 ，只有Cr才是显著提高钢基体电极电位常用的元素。
Cr 能提高钢的电极电位，但不是呈线性关系、如图5.1所示。实验证呼钢的电极电位随合金元素的增加，存在着
一个量变到质变的关
系，遵循1/8规律。当
Cr含量达到一定值时
即1,8原子(l,8、2
,8、3/8„„)时 ，
电极电位将有一个突
变。因此，几乎所有的
不锈钢中，Cr含量均在
12.%5(原子)以上，
即
11.7%(质量)以上。
(2)加入合金元
素使钢的表面形成一
层稳定的、完整的与钢
的基体结合牢固的纯化膜。从而提高钢的耐化学腐蚀能力。如在钢中加入 Cr,Si.Al等合金元素 ，使钢的表层形成致密的CrO,SiO,AlO等氧化膜 ，就可提高钢的耐蚀性。 23223
(3)加入合金元素使钢在常温时能以单相状态存在，减少微电池数目从而提高钢的耐蚀性。如加入足够数量的Cr或Cr,Ni,使钢在室温下获得单相铁 素体或单相奥氏体。
(4)加入Mo、Cu等元素，提高钢抗非氧化性酸腐蚀的能力。
(5)加入Ti，Nb等元素，消除Cr的晶间偏析，从而减轻了晶问腐蚀倾向。
(6)加入Mn、N等元素，代替部分Ni获得单相奥氏体组织，同时能大大提高铭不锈钢在有机酸中的耐蚀性。
17.4不锈钢的种类和特点
不锈钢有两种分类法:一种是按合金元素的特点，划分为铬不锈钢和铬镍不锈钢;另一种是按在正火状态下钢的组织状态 ，划分为M不锈钢、F不锈钢、A不锈钢和A一F双相不锈钢。 一、马氏体不锈钢
典型的马氏体不锈钢钢号有1Cr13,4Cr13和9Cr18等
1Cr13钢加工工艺性能良好。可不经预热进行深冲、弯曲、卷边及焊接。2Crl3冷变形前不要求预热，但焊接前需预热 ，ICrl3、2Cr13主要用来制作耐蚀结构件如汽轮机叶片等，而3Cr13、4Cr13主要用来制作医疗器械外科手术刀及耐磨零件;9Cll8可做耐蚀轴承及刀具。 二、铁素体不锈钢
铁素作不锈钢的含Cr量一般为13,,30,合碳量低于0.25%。有时还加入其它合金元素。air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
金相组织主要是台铁 素体，加热及冷却过程中没有α<=>γ转变，不能用热处理进行强化。抗氧
-化性强，加入合金元素比可在有机酸及 含Cl的介质中有较强的抗蚀。同时，它还具有良好的热加工性及一定的冷加工性。铁体不锈钢主要用来制作要求有较高的耐蚀性而强度要求较低的构件，广泛用于制造生产硝酸、氮肥等设备和化工使用的管道等。
典型的铁案体不锈钢有Crl7型、Cr25型和Cr28型,其成分性能及热处理工艺如表所示 三，奥氏体不锈钢
奥氏作不锈钢是克服马氏作不锈钢耐蚀性不足和铁素体不锈钢脆性过大而发展起来的。基本成分为Crl8,、Ni8,简称18,8钢。其特点是合碳量低于0.1,，利用Cr、Ni配合获得单相奥氏体组织。
奥氏作不锈钢一般用于制造生产硝酸、硫酸等化工设备构件、冷冻工业低温设备构件及经形变强化后可用作不锈钢弹簧和钟表发条等。
奥氏体不锈钢具有良好的抗均匀腐蚀的性能，但在局部抗腐蚀方面，仍存在下列问题:
1.奥氏体不锈钢的晶间腐蚀
奥氏作不锈钢在450,850?保温或缓慢冷却时，会出现晶问腐蚀。合碳量越高，晶间蚀倾向性越大。此外，在焊接件的热影响区也会出现 晶间腐蚀。这是由于在晶界上析出富Cr的CrC。236使其周围基体产生贫铬区，从而形成腐蚀原电池而造成的。这种晶间腐蚀现象在前面提到的铁 素体不锈钢中也是存在的。
工程上常采用以下几种方法防止晶间腐蚀:
(1)降低钢中的碳量，使钢中合碳量低于平衡状态下在奥氏体内的饱和溶解度，即从根本上解决了铬的碳化物(CrC)在晶界上 析出的问题。通常钢中合碳量降至0.03,以下即可满足抗236
晶间腐蚀性能的要求。
(2)加入Ti、Nb等能形成稳定碳化物(TiC或NbC)的元素，避免在晶界上析出CrC，即236可防上奥氏体不锈钢的晶间腐蚀。
(3)通过调整钢中奥氏体形成元素与铁素体形成元素的比例，使其具有奥氏体+铁索体双相组织，其中铁素体占5,一12,。这种双相组织不易产生晶间腐蚀。
(4)采用适当热处理工艺，可以防止晶间腐蚀，获得最佳的耐蚀性。
2.奥氏体不锈钢的应力腐蚀
应力(主要是拉应力)与腐蚀的综合作用所引起的开裂称为应力腐蚀开裂，简称SCC(Stress Crack Corrosion)。奥氏体不锈钢容易在含氯离子的腐蚀介质中产生应力腐蚀。当合Ni量达到8,一10,时，奥氏体不锈钢应力腐蚀倾向性最大，继续增加 含Ni量至45,,50,应力腐蚀倾向逐渐减小，直至消失。
防止奥氏体不锈钢应力腐蚀的最主要途径是加入Si2,,4,并从冶炼上将N含量控制在0.04,以下。此外还应尽量减少P、Sb、Bi、As等杂质的含量 。另外可选用A-F双用钢，它在--Cl和OH介质中对应力腐蚀不敏感。当初始的微细裂纹遇到铁素体相后不再继续扩展，体素体含量应在6%左右。
3.奥氏作不锈钢的形变强化
单相的奥氏体不锈钢具有良好的冷变形性能，可以冷拔成很细的钢丝，冷轧成很薄的钢带或钢管。经过大量变形后，钢的强度大力提高 ，尤其是在零下温区轧制时效果更为显著。抗拉强度可达 2 000 MPa以上。这是因为除了冷作硬化效果外，还叠加了形变诱发M转变。
奥氏作不锈钢经形变强化后可用来制造不锈弹簧、钟表发条、航空结构中的钢丝绳等。形变后若需焊接，则只能采用点焊工艺、形变使应力腐蚀倾向性增加 。并因部分γ->M转变而产生铁磁性，在使用时(如仪表零件中)应予以考虑。
再结晶温度随形变量而改变，当形变量为60,时，其再结晶温度降为650?冷变形奥氏体不锈钢再结晶退火温度为850,1050?，850?则需保温3h，1050?时 透烧即可，然后水冷。 air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
4.奥氏作不锈钢的热处理
奥氏体不锈钢常用的热处理工艺有:固溶处理、稳定化处理和去应力处理等。
(1)固溶处理。将钢加热到1050,1150?后水淬，主要目的是使碳化物溶于奥氏体中，并将此状态保留到室温 ，这样钢的耐蚀性会有很大改善。如上所述，为了防止晶问腐蚀，通常采用固溶化处理，使CrC溶于奥氏体中，然后快速冷却。对于薄壁件可采用空冷 ，一般情况采236
用水冷。
(2)稳定化处理。一般是在固溶处理后进行，常用于含Ti、Nb的18-8钢，固处理后，将钢加热到850,880?保温后空冷 ，此时Cr的碳化物完全溶解，脱而钛的碳化物不完全溶解，且在冷却过程中充分析出，使碳不可能再形成格的碳化物，因而有效地消除了晶间腐蚀。
(3)去应力处理。去应力处理是消除钢在冷加工或焊接后的残余应力的热处理工艺一般加热到300,350?回火。对于不 含稳定化元素Ti、Nb的钢，加热温度不超过450t，以免析出铬的碳化物而引起晶间腐蚀。对于超低碳和合Ti、Nb不锈钢的冷加工件和焊接件，需在500,950?,加热 ，然后缓冷，消除应力(消除焊接应力取上限温度)，可以减轻晶间腐蚀倾向并提高钢的应力腐蚀抗力。
四、奥氏体-铁素体双相不锈钢
在奥氏作不锈钢的基础上，适当增加Cr含量并减少Ni含量，并与回溶化处理相配合，可获得具有奥氏体和铁素体的双相组织( 含40,60,δ-铁素体)的不锈钢，典型钢号有0Cr21Ni5Ti、1Cr21Ni5Ti、OCr21Ni6Mo2Ti等。双相不锈钢与里氏体不锈钢相比有较好的焊接性，焊 后不需热处理，而且其晶间腐蚀、应力腐蚀倾向性也较小。但由于含Cr量高，易形成ζ相，使用时应加以注意。
第18章 耐热钢及高温合金
各种动力机械，加热电站中的锅炉和蒸汽轮机、航空和舰艇用的燃汽轮机以及原子反应堆工程等结构中的许多结构件是在高温状态下工作的。工作温度的升高 ，一方面影响钢的化学稳定性;另一方面降低钢的强度。为此，要求钢在高温下应具有
(1)抗蠕变、抗热松弛和热疲劳性能及抗氧化能力
(2)在一定介质中耐腐蚀的能力以及足够的韧性
(3)具有良好的加工性能及焊接检
(4)按照不同用途有合理的组织稳定性。
耐热钢是指在高温下工作并具有一定强度和抗氧化耐腐蚀能力的钢种，耐热钢包括热稳定钢和热强钢。热稳定钢是指在高温下抗氧化或执高温介质腐蚀而不破坏的钢种 ，如炉底板、炉栅等。它们工作时的主要失效形式是高温氧化。而单位面积上承受的载荷并不大。热强钢是指在高温下有一定抗氧化能力并具有足够强度而不产生大量变形或
断裂的钢种，如高温螺栓、涡轮叶片等。它们工作时要求承受较大的载荷，失效的主要原因是高温下强度不够。
18.1钢的热稳定性和热稳定钢
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
一、钢的抗氧化性能及其提高途径
工件与高温空气、蒸汽或燃气相接肽表面要发生高温氧化或腐蚀破坏。因此，要求工件必须具备较好的热稳定性。
除了加入合金元素方法外，目前还采用渗金属的方法，如渗Cr、渗Al或渗Si，以提高钢的抗氧化性能。
二、热稳定钢
热稳定钢(又称抗氧化钢广泛用于工业锅炉中的构件，如炉底板、马弗罐、辐射管等这种用途的热稳定钢有铁素体F型热稳定钢和奥氏 体A型热稳定的钢两类。
F型热稳定钢是在F不锈钢的基础上进行抗氧化合金化而形成的钢种、具有单相F基体，表面容易获得连续的保护性氧化膜。根据使用温度 ，可分为Cr13型钢、Cr18型钢和 Cr25型钢等。F型热稳定钢和F不锈钢一样，因为没有相变，所以晶粒较粗大，韧性较低，但抗氧化性很强。
A型热稳定钢是在A型不锈钢的基础上进一步经Si、Al抗氧化合金化而形成的钢种。A型热稳定钢比F型热稳定钢具有更好的工艺性能和热强性。但这类钢因消耗大量的Cr、Ni资源，故从50年代起研究了Fe-Al,Mn系和Cr,Mn-N系热稳定钢 ，并已取得了一定进展。 18.2 金属的热强性
一、高温下金属材料力学性能特点
在室温下，钢的力学性能与加载时间无关，但在高温下钢的强度及变形量不但与时间有关，而且与温度有关，这就是耐热钢所谓的热强性。热强性系指耐热钢在高温和载荷共同作用下抵抗塑性变形和破坏的能力。由此可见在评定高温条件下材料的力学性能时，必须用热强性来评定。热强性包括材料高温条件下的瞬时性能和长时性能。
瞬时性能是指在高温条件下进行常现力学性能试验所测得的性能指标。如高温拉伸、高温冲击和高温硬度等。其特点是高温、短时加载 ，一般说来瞬时性能P是钢热强性的一个侧面，所测得的性能指标一般不作设计指标，而是作为选择高温材料的一个参考指标。
长时性能是指材料在高温及载荷共同长时间作用下所测得的性能、常见的性能指标有:蠕变极限、持久强度、应力松他高温疲劳强度和冷热疲劳等(详见金属力学性能地这是评定高温材料必须建立的性能指标。
二、热泪性的影响因表及其提高途径
1.影响耐热钢热强性的因素
随着温度的升高，耐热钢抵抗塑性变形和断裂的能力不断降低，这主要是由以下两个因素造成的:
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
(1)影响耐热钢的软化因素。随着温度的升高、钢的原子问结合力降低原子扩散系数增大，从而导致钢的组织由亚稳态向稳定态过渡、如第二相的聚集长大、多相合金中成分的变化、亚结构祖化及发生再结晶等这些因素都导致钢的软化。
(2)形变断裂方式的变化。金属材料在低温下形变时一般都以滑移方式进行，但随着温度的升高，载荷作用时间加长，这时不仅有滑移，而且还有扩散形变及品界的滑动与迁移等方式。扩散形变是在金属发生变形但看不到滑移线的情况下提出的。这种变形机制是高温时金属内原子热运动加剧 ，致使原子发生移动，但在元外力作用了原子的移动无方向性，故宏观上不发生变形;当有外力作用时，原子移动极易发生且有方向性，因而促进变形。当温度升高时，在外力作用下晶界也会发生滑动和迁移 ，温度越高，载荷作用的时间愈长，晶界的滑动和迁移就越明显。
常温下金属的断裂在正常情况下均属穿品断裂，这是由于晶界区域晶格畸变程度大、晶内强度低于晶界强度所致。但随温区升高 ，由于晶界区域品格畸变程度小使原子扩散速度增加，晶界强厦减弱。温度越高，载荷作用时间越长，则金属断裂方式更多地呈晶间断裂。 2.提高钢的热强性途径
基于上述分析，提高钢的热强性主要途径省三个方面基体强化煤二相强化、晶界强化。
(1)基体强化。主要出发点是提高基体金属的原子问结合力、降低固溶体的扩散过程。研究表明，从钢的化学成分来说，凡是熔点高、自扩散系数小店首提高钢的再结晶温度的合金元素固溶于基体后都能提高钢的热强性。如h基及M是高温合金中主要的固 溶强化元素有Mo、W、Co和Cr等。从固溶体的晶格类型来说，奥氏作基比铁素作基体的热
强性高。这是由于奥氏体的点阵排列较铁素体致密，扩散过程不易进行。如在铁基合金中，Fe、C，Mo等元素在A中的扩散系数显著低于在F中的扩散系数，这就使回复和再结晶过程减慢，第二相聚集速 度减慢，从而使钢在高温状态下不易软化。
(2)第二相强化。主要出发点是要求第二相稳定，不易聚集长大批在高温下长期保持细小均匀的弥散状态，因此对第二 相粒子的成分利结构有一定的要求。耐热钢大多用难塔台金碳化物作强化相，如 MC，MC、MC等。为获得更高的热强性 ，可用热稳定性更高的全属间化合物。2366
如Ni3(TiAl),Ni3Ti,Ni3Al等作为基体的强化相。
(3)晶界强化、为减少高温状态下晶界的滑动，主要有下列途径:
?减少晶界、需适当控制钢的晶粒度。晶粒过细品界多，虽然阻碍晶内滑移，但晶界滑动的变形量增大、塑变 抗力降低。晶粒过大，钢的脆性增加，所以要适当控制耐热钢的晶粒厦，一般在2,4级晶粒度时能得到较好的高温综合性能。
?净化晶界。钢中的S和P等低熔点杂质易在晶界偏聚，并和铁易于形成低熔点共晶体，从air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
而削弱晶界强度，使钢的热强性下降。着钢中加入B、稀土等 元素，可形成高熔点的稳定化合物，在结晶过程中可作为晶核，使易熔杂质从晶界转入晶内，从而使晶界得到净化，强化了晶界。
?填补晶界上空位、晶界处空位较多，使扩散易于进行，是裂纹易于扩展的地力加入B、Ti、Zr等表面活化元素，可以填充晶界空位 ，阻碍晶界原子扩散，提高蠕变抗力。
?晶界的沉淀强化。如果在晶界上沉淀出不连续的强化相，将使塑性变形时沿晶界的滑移及裂纹沿晶界的扩展受阻，使钢的热强性提高。例如用二次 固溶处理的方法可在品界上析出链状的CrC化合物，从而提高钢的热强性。 236
除此之外，还可用形变热处理方法将晶界形状改变为锯齿状品界和在晶内造成多边化的亚晶界，进一步提高钢的热强性。
18.3 a-Fe基热强钢
a-Fe基热强钢包含珠光体型热强钢和马氏体型热强钢、这两类钢在加热和冷却时会发生a裆7转变，故使进一步提高使用温度受到限制。这类钢在中温下有较好的热强性、热稳定性及工艺性能 ，线膨胀系数小，合碳量也较低，价格低廉，是适宜在600,650?以下温区使用的热强钢，广泛应用于制造锅炉、汽轮机及石油提炼设备等。
一，珠光作型热强钢
珠光体热强钢按合碳量和应用特点可分为低碳珠光体效强钢和中碳珠光体热强钢两类、前者主要用于制作锅炉钢管，后者主要用于制作汽轮机等耐热紧固件、汽轮化转子(包含轴、叶轮)等，
珠光体热强钢的工作温度虽然不高，但由于工作时间长，加之受周围介质的腐蚀作用，在工作过程中可能产生下述的组织转变和性能变化。
1.珠光体的球化和碳化物的聚集
珠光体热强钢在长期高温作用下，其中的片状碳化物转变成球状，分散细小的碳化物聚集成大颗粒的碳化物。这种组织的变化将引起钢的强烈较优，导致蠕变极限、持久强度、屈服极限的降低。这种转变是一种由不平衡状态向平衡状态过渡的自发进行的过处是通过碳原子的扩散进行的。
影响碳化物球化及聚集的主要因素是温度、时间和化学成分。碳钢最容易球化，合碳量增加会加速球化过程。在钢的成分中几代溶入固溶体并降低碳的扩散速度和增加碳化物中原子结合力的元素如 Cr、MO、V、Ti等均能阻碍或延缓球化及聚集过程。
2.钢的石墨化
钢件在工作温度和应力长期作用下，会使碳化物分解成游离的石墨，这个过程也是自发进行air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
的，称为P热强钢的石墨化过程、它不但消除了碳化物的作用，而 且石墨相当于钢中的小裂纹，使钢的强度和塑性显著降低而引起钢件脆断。这是一种十分危险的转变过程。
向钢中加入Cr、Ti、Nb等合金元素，均能阻止石墨化过程;另外，在冶炼时不能用促进石墨化的Al脱氧;采用退 火或回火处理也能减少石墨化倾向。
3.合金元素的再分布
耐热钢长期工作时，会发生合金元素的重新分配现象，即碳化物形成元素Cr、Mo向碳化物内扩散、富集，而造成固溶体合金元素贫化，导致热强性下降。生产中经常采用加入强碳物形成元素V、Ti、Nb等从而阻止合金元素扩散聚集的再分队提高钢的热强性。
4.热脆性
珠光体型不锈钢在某一温度下长期工作时，可能发生冲击韧性大幅度下降，突然发生脆性断裂的现象。这种脆性积为热脆性。它与在该温度下某种新相的析出有关。防上热脆性可采取如下措施 ，使钢的长期工作温度避开脆性区温度;冶炼时尽量降低队P含量:加入适量的W、Mo等合金元素，已发生热脆性的钢，可采用600,650?高温回火后快冷的方法加以消除。
珠光体热强钢的热处理，一般经正火( Ac3， 50?)处理所得到的组织是不稳定的，为了保证在使用温度下组织性能稳且一般采用高于使用温度100?的回 火处理。 二、马氏作型热弹钢
这类钢主要用于制造汽轮机叶片和汽轮机或柴油机的排气阀。
应用最早的是Cr13型钢，它是一种马氏体不锈钢。经热处理后，可获得较高的机械性能和良好的耐热性。
Crl3型马氏体效强钢的热处理工艺通常采用1000,1150?油淬，650,750?高温回火得到回火屈氏体和 回火索氏体组织，以保证在使用温度下组织和性能的稳定。它们用于制造像用温度低于588?的汽轮机和燃气轮机的叶片。
18.4 γ,Fe基热强钢
珠光体、马氏体类热强钢一般使用温度在650?以下，不能适用于更高的使用温度其原因在于，无论是珠光作基还是马氏体基热强钢，其基体相都是铁 素体，即先天不足。因此必须更换基作组织，即用奥氏体。负数氏体基钢之所以比Fe基钢具有更高的热强性，其原因在于:γ-Fe晶格的原子间结合力比α,Fe晶格的原子间结合力大;γ-Fe扩散系
数小;γ-Fe的再结晶温度高(α,Fe再结晶温度为450,600?，而γ-Fe再结晶温度大于800?。
γ-Fe基热强钢还具有良好的可焊性、抗氧化性、高的塑性和冲击韧性。这类钢也有一些缺air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
点，如室温屈服强度低、压力加工及切削性能较差、导热性差，而在温度变化时效应力大，故抗热疲劳性能差。但是由于热强性高，所以得到了充分的发展和广泛的应用。
第19章 铸铁
铸铁不是纯铁，它是一种以Fe、C、Si为主要成分且在结晶过程中具有共 晶转变的多元铁基合金。化学成分一般为:C2.5,—4.0,、Si1.0,一3，0,、P0.4%,1.5,、S0.02,—02,。为了提高铸铁的机械性能 ，通常在铸铁成分中添加少量Cr、Ni、C。、Mi、等合金元素制成合金铸铁。
19，1铸铁的特点和分类
一、铸铁的特点
1.成分与组织特点
铸铁与碳钢相比较，其化学成分中除了有较高的C、Si含量外(C2.5,,4，0%、Si1.0,一3.0,)，还含有较高的杂质元素Mn、P，S，在特殊性能的合金铸铁中，还含有某些合金元素。所有这些元素的存在及其含量，都将直接影响铸铁的组织和性能。
由于铸铁中的碳主要是以石墨(G)形式存在的，所以铸铁的组织是由金属基体和石墨所组成的。铸铁的金属基体有珠光体、铁素体和珠光 体加铁素体三类，它们相当于钢的组织。因此，铸铁的组织特点，可以看成是在钢的基体上分布着不同形状的石墨。
2.铸铁的性能特点
铸铁的抗拉强度、塑性和韧性要比碳钢低。虽然铸铁的机械性能不如钢，但由于石墨的存在，却赋予铸铁许多为钢所不及的性能。如良好的耐磨性、高消振性、低缺口敏感性以及优良的切削加工性能。此外 ，铸铁的碳含量高，其成分接近于共晶成分，因此铸铁的熔点低，约为1200?左右，铁水流动性好，由于石墨结晶时体积膨胀，所以传送收缩率小，其铸造性能优于钢，因而通常采用铸造方法制成铸件使用，故称之为铸铁。
二、铸铁的分类
铸铁的分类方法很多。根据碳存在的形式可分为三种:
1.白口铸铁(简称白口铁)
白口铸铁中的碳主要以渗碳体(Cm)形式存在，断口呈白亮色。其性能硬而脆，切削加工困难。除少数用来制造硬度高、耐磨、不需要加工的零件或表面要求硬度高、耐磨的冷硬铸件外(如破碎机的压板、轧辊、火车轮等 )，还可作为炼钢原料和可锻铸铁的毛坯。 2.灰口铸铁(简称灰口铁)
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
灰口铸铁中的碳主要以片状石墨的形式存在，断口呈灰色。灰口铸铁具有良好的铸造性能和切削加工性能，且价格低廉，制造方便，因而应用比较广泛。
3.麻口铸铁(简称麻口铁)
麻口铸铁中的碳既以渗碳体形式存在，又以石墨状态存在。断口来杂着白亮的游离渗碳体和暗灰色的石墨，故称为麻口铁。生产中很少用麻口铁。
根据石墨形状的不同，将铸铁分为以下四种:
(1)灰口铸铁，铸铁中的石墨形状呈片状。
(2)蠕墨铸钟持铁中的石墨大部分为短小蠕虫状
(3)球墨铸铁(又称玛铁、玛钢)，铸铁中的石墨是不规则团絮状。
(4)球墨铸铁:铸铁中的石墨呈球状。
此外，为了获得某些特殊性能，应使铸铁中的常规元素高干规定的含量，并且加入一定的合金元素，此称之为 特殊性能铸铁。例如、耐磨铸铁、耐热铸铁和耐蚀铸铁等。 19，2铸铁的结晶
通过金属学的学习我们已经知道，铸铁的结晶过程和组织转变依化学成分和铸造工艺条件不同，可以按Fe-FeC系进行或者按Fe-G系进行。研究铸铁时为了方便起见 ，通常将这两种状态3
图叠加在一起称为Fe-C合金双重状态图，如图所示 。
由图可见，亚共晶成分的发口铸铁(简称灰铸铁)结晶时，首先拆出的是初生奥氏体A，以后残留下的液相再经过共晶转变 ，变为固态。共晶转变完毕后继续冷却时，还要发生碳自A中脱港析出那以后的共折转变，完成结晶过程，形成亚共晶铸铁的最终纷纷通常把初生A的析出和以后共晶转变称为铸铁的一次结晶;而把凝固后进行的碳自A中的 脱溶、共析转变称为二次结晶。
表 灰铸铁的结晶过程
一次结晶决定了铸铁的晶粒大小、石墨形状和分布，二次结晶决定了铸铁的基体组织。因此。要控制铸铁的组织，就必须控制这两个结晶过程。
19.3 铸铁的石墨化
一，铸铁的石墨化过程
铸铁中石墨的形成过程称为石墨化过程。铸铁组织形应的基本过程就是铸铁中石墨的形成过程。因此，了解石墨化过程的条件与影响因素对掌握铸铁材料的组织与性能是十分重要的。
,C合金双重状态图，铸铁的石墨化过程可分为三个阶段: 根据Fe
第一阶段，即液相亚共晶结晶阶段。包括，从过共晶成分的液相中直接结晶出一次石墨和共air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
晶成分的液相结晶出奥氏体加石墨由一次渗碳体和共 晶渗碳体在高温退火时分解形成的石墨。
中间阶段，即共晶转变亚共折转变之间阶段。包括从奥氏体中直接析出二次石墨和二次渗碳体在此温度区间分解形成的石墨。
第二阶段，即共折转变阶段。包括共折转变时，形成的共析石墨和共析渗碳体退火时分解形成的石墨。
铸铁石墨化过程进行的程度与铸铁组织的关系概括于表中
二、影响铸铁石墨化的因素
铸铁的组织取决于石墨化进行的程度，为了获得所需要的组织，关键在于控制石墨化进行的程度。实践证明，铸铁化学成分、铸铁结晶的的冷却速度及铁水的过热和 静置等诗多因素都影响石墨化和铸铁的显微组织。
1.化学成分的影响
各元素对待铁石墨化的影响可定性地列于表中。各元素对石墨形状、分布的影响定性地列于表中。
由表可见，恃铁中常见的C，Si、Mn、P、S中，C，Si是强烈促进石墨化的元素，S是强烈阻碍石墨化的元素。实际上各元素对铸铁的石墨化能力的影响极为复杂。其影响与各元素本身的含量以及是否与其它元素发生作用有关 ，如Ti、Zr、B、Ce、Mg等都阻碍石墨化，但若其含量极低(如B、Ce,0.01,，T,0.08,)时，它们又表现出有促进石墨化的作用。 2.冷却速度的影响
一般来说，铸件冷却速度趋缓慢，就越有利于按照Fe-G稳定系状态图进行结晶与转变，充分进行石墨化;反之则有利于按照 Fe-FeC亚稳定系状态图进行结晶与转变，最终获得 白口铁。3
尤其是在共析阶段的石墨化，由于温度较低，冷却速度增大，原子扩散困难，所以通常情况下，共折阶段的石墨化难以充分进行。
铸铁的冷却速度是一个综合的因素，它与浇注温度、传型材料的导热能力以及铸件的壁厚等因素有关。而且通常这些因素对两个阶段的影响基本相同。
提高浇注温度能够延缓铸件的冷却速度，这样既促进了第一阶段的石墨化，也促进了第二阶段的石墨化。因此，提高浇注温度在一定程度上能使石墨粉化 ，也可增加共析转变。 3.铸铁的过热和高温静置的影响
在一定温度范围内，提高铁水的过热温度，延长高温静置的时间，都会导致铸铁中的石墨基作组织的细化，使铸铁强度提高。进一步提高过热度，铸铁的成核能力下降，因而使石墨形态变差，甚至出现自由渗联体，使强度反而下降，因而存在一个‘临界温度’。临界温度的高低，主air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
要取决于铁水的化学成分及铸件的冷却速 度一般认为普通灰铸铁的临界温度约在1500一1550?左右，所以总希望出铁温度高些。
19.4灰铸铁
灰铸铁是一种断面是灰色，碳主要以片状石墨形式出现，是应用最为广泛的一种铸铁。灰铸铁的铸造性能、切削性、耐磨性和吸 震性都优于其它各类铸铁，而且生产方便、品率高、成本低。因此，在工农业生产中友铸铁获得广泛应用，在各类铸铁的总产量中点80,以上。 一，灰铸铁的牌号、化学成分反显微组织
根据发铸铁分类国家标准 GB 9439一88，我国灰铸铁的牌号分为六级。
“HT”表示灰铁二字汉语拼音的第一个大写字母，其后数字表示抗拉强度。发铸铁的化学成分见表。
灰铸铁的显微组织是由片状石墨和金属基体所组成的。金属基体俄共析阶段石墨化进行的程度不同可分为铁素体、铁素体-珠光体作和珠光体三种。相应有三种不同基体组织的灰铸铁 ，它们的显微组织分别如图与图所 示。
普通灰铸铁的金属基体以珠光作为主，并合有少量铁素体;高强度铸铁主要是珠光作基体，属于铁素体基体的主要是高硅铸铁。
二、灰铸铁的性能和用途
灰铸铁的性能与其他学成分和组织有密切的联系。
1.优良的铸造性能
由于友铸铁的化学成分接近共晶点，所以铁水流动性好，可以铸造非常复杂的零件。另外，由于石墨比容较大，使铸件凝固时的收缩量减少，可简化工艺，减轻铸件的应力并可得到致密的组织。
2，优良的耐磨性和消震性
石墨本身具有润滑作用，石墨掉落后的空洞能吸附和储存润滑油，使铸件有良好的耐磨性。此外，由于铸件中带有硬度很高的磷共晶，又能使抗磨能力进一步提高，这对于制备活塞环、气缸套等受摩擦零件具有重要意义。
石墨可以阻止后动的传播，灰铸铁的消夸大能力是钢的10倍，常用来制作承受振动的机床底座。
3.较低的缺口敏感性和良好的切削加工性能
灰铸铁中由于石墨的存在，相当于存在很多小的缺口时表面的缺陷、缺口等几乎没有敏感性，因此，表面的缺陷对铸铁的疲劳强度影响较小 ，但其疲劳强度比钢要低。由于发铸铁中的石墨air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
可以起断屑作用和对刀具的润滑起减障作用，所以其可切削加工性是优良的。 4.灰铸铁的机械性能
友铸铁的抗拉强度、塑性、韧性及弹性模量都低于碳素锈钢，如表所示。灰铸铁的抗压强度和硬度主要取决于基体组织。灰铸铁的抗压强度一般比抗拉强度高出三四倍 ，这是灰铸铁的一种特性。因此，与其把灰铸铁用作抗拉零件还不如做耐压零件更适合。这就是广泛用作机床床身和支柱受耐压零件的原因。
19.5 提高铸铁性能的途径
一、铸铁石墨细伦强化——孕育处理
为了细化灰铸铁的组织，提高铸铁的机械性能，并使其均匀一致。通常在浇注前往铁水中加和少量强烈促进石墨化的物质 ，即孕育剂)进行处理，这一处理过程称为孕育处理。经过孕育处理的灰铸铁称孕育铸铁。
常用的孕育剂有破铁、硅钙、稀土台金等，其中最常用的是含有75,Si的铁合金。孕育剂的加入量大致在0.2,,0.5,，应视铸件厚薄而定。孕育剂的作用是促使石里非自发形核 ，因而孕育铸铁的全相组织是在细密的珠光体基体上，均匀分布细小的石墨，其抗拉强度可达300
2一400 MPa，硬度可达HB170—270，α可达3,8 J,cm、延伸率达0.5,左右 ，都比普通灰k
铸铁高。
二、铸铁的石墨球化强化——球化处理
1.球墨铸铁的生产
石墨呈球状的铸铁称为球墨铸铁，简称球铁。球铁是用灰口成分的铁水经球化处理和孕育处理两制得的。
2、球铁的组织和性能特点
球墨铸铁中的石墨呈球状，它对基体的破坏作用小，基体强度利用率可达70,,90,。另外。球铁可通过热处理充分发挥基体的性能潜力，所以球铁具有较好的机械性能。抗拉强度最高
722可达150x10N/m，延伸率可达25%。另外，它的屈强比 很高，α可达8-15J,cm。 k
3.球墨铸铁的牌号，化学成分和用途
根据国家标准 GB,348,,88规定，球铁分为八个牌号，牌号中‘QT’是球铁二字汉语拼音的字头，其后二级数字分别表示最低抗拉强度和最低延伸率。表 中列出了球铁的化学成分和力学性能。
球铁具有上述优异的机械性能、有时可用它代替碳素钢，应用于负荷较大受为复杂的零件如珠光air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
体基的球铁常用于制造汽车、拖拉机中的曲轴、连杆、凸轮等。还可做大型水压机的工作缸、缸套及活塞。而铁素作基的球铁多用于制造受压阀门、汽车后桥壳等。
19.6 可锻铸铁
它是由白口铸件经热处理而得的一种高强度铸化与灰铸铁相比，它具有较高的强度、塑性、韧性，而耐磨性和城探性优于普通碳素钢，所以可部分代替碳钢、合金钢和有色金属。 19.7 特殊性能铸铁
在普通铸钟基础上加入某些合金元素可使铸铁具有某种特殊性能，如耐磨性、耐热性或腐蚀性等，从而形成一类具有特殊性能的合金铸铁。合金铸铁可用来制造在高温、高 磨擦或耐蚀条件下工作的机器零件。
一、耐磨铸铁
根据工作条件的不同，耐磨铸铁可以分为减摩铸铁和抗磨铸铁两类。减磨铸铁用于制造在润滑条件工作的零件，如机床床身、导轨和汽缸套等。这些零件要求较小的摩擦系数。抗磨 铸铁用来制造在于摩擦条件下工作的零件，如轧辊、球磨机磨球等。
二、耐热铸铁
铸铁在高温条件下工作、通常会产生氧化和生长等现象。氧凡是指铸铁在高温下受氧化性气氛的侵蚀，在铸件表面发生的化学腐蚀的现象。由于表面形成氧化皮，减少了铸件的有效断面，因而降低了铸件的承载能力。生长是指铸铁在高温下反复加热冷却时发生的不可塑的体积长大，造成零件尺寸增大，并使机械性能降低。铸件在高温和负荷作用了，由于氧化和生长最终导致零件变形、翘曲、产生裂纹，甚至破裂。所以铸铁在高温下抵抗破坏的能力通常指铸铁的抗氧化性和抗生长能力。耐热铸铁是指在高温条件下具有一定的抗氧化和抗生长性能，并能承受一定载荷的待钱。
三，耐蚀铸铁
普通铸铁的耐蚀性是很差的，这是因为铸铁本身是一种多相合金，在电解质中各相具有不同的电极电位，其中以石墨的电极电位最高，渗碳体次之，铁素体最低。电位高的相是阴极，电位低的相是阳极，这样就形成了一个微电池，于是作阳极的铁素作不断被消耗掉，一直深入到铸铁内部。
提高铸铁的耐蚀性的手段主要是加入人合金元素以得到有利的组织和形成良好的保护膜。铸铁的基作组织最好是致密、均匀的单相组织、即A或F。中等大小又不相互连贯的石墨对耐蚀性有利。至于石墨的形状，则以球状或团絮状为有利。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
19.8 铸铁的热处理
铸铁生产除适当地选择优学成分以得到,定的组织外，热处理也是进一步调整和改进基体组织以提高铸铁性能的一种重要途径。铸铁的热处理和钢的热处埋有相同之处 ，也有不同之处。铸铁的热处理一般不能改善原始组织中石墨的形态和分布状况。对灰口铸铁来说，由于片状石墨所引起的应力集中效应是对铸铁性能起主导作用的困素，因此对
灰口铸铁施以热处理的强化效果远不如钢和球铁那样显著。故友口铸铁热处理工艺主要为退火、正火等。对于球铁来说，由于石墨呈球状，对基体的割裂作用大大减轻，通过热处理可使基作组织充分发挥作用，从而可以显著改善球性的机械性能。 故球铁像钢一样，其热处理工艺有退火、正火、调质、多温淬火、感应加热淬火和表面化学热处理等。
铸铁的热处理工艺:
1.消除应力退火
由于铸件壁厚不均匀，在加热，冷却及相变过程中，会产生效应力和组织应力。另外大型零件在机加工之后其内部也易残存应力，所有这些内应力都必须消除。去应力退火通常的加热温度为500,550?保温时间为2,8h，然后炉冷(灰口铁)或空冷(球铁)。采用这种工艺可消除 铸件内应力的90,95,，但铸铁组织不发生变化。若温度超过550?或保温时间过长，反而会引起石墨化，使铸件强度和硬度降低。
2.消除铸件白口的高温石墨化退火
铸件冷却时，表层及薄截面处，往往产生白口。白口组织硬而脆、加工性能差、易剥落。因此必须采用退火(或正火)的方法消除白口组织。退火工艺为:加热到550,950?保温2,5 h，随后炉冷到500—550?再出炉空冷。在高温保温期间 ，游高渗碳体和共晶渗碳体分解为石墨和A，在随后护冷过程中二次渗碳体和共析渗碳体也分解，发生石墨化过程。由于渗碳体的分解，导致硬度下降，从而提高了切削加工性。
3.球铁的正火
球铁正火的目的是为了获得珠光体基体组织，并细化晶粒，均匀组织，以提高铸件的机械性能。有时正火也是球铁表面淬火在组织上的准备、正 火分高温正火和低温正火。高温正火温度一般不超过950,980?，低温正火一般加热到共折温度区间820,860?。正火之后一般还需进行四人处理，以消除正火时产生的内应力。
4.球铁的淬火及回火
ff 为了提高球铁的机械性能，一般铸件加热到A以上30,50?(A代表加热时A形成终了c1c1
温度) ，保温后淬入油中，得到马氏体组织。为了适当降低淬火后的残余应力，一般淬火后应air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
进行回火，低温回火组织为回火马氏作加残留贝氏体再加球状石墨。这种组织耐磨性好 ，用于要求高耐磨性，高强度的零件。中温回火温度为350—500?回火后组织为回火屈氏体加球状石墨，适用于要求耐磨性好、具有一定效稳定性和弹性的厚件。高温 回火温度为500—60D?，回火后组织为回火索氏作加球状石墨，具有韧性和强度结合良好的综合性能，因此在生产中广泛应用。
5.球铁的多温淬火
球铁经等温淬火后可以获得高强度，同时兼有较好的塑性和韧性。多温淬火加热温度的选择
f主要考虑使原始组织全部A化、不残留F，同时也避免A晶粒长大。加热温度一般采用A以上c130,50?，等温处理温度为0,350?以保证获得具有综合机械性能的下贝氏体组织。稀土镁铝
2球铁等 温淬火后ζ=1200,1400MPa，α=3,3.6J,cm，HRC,47,51。但应注意等温淬火后再bk
加一道回火工序。
6.表面淬火
为了提高某些铸件的表面硬度、耐磨性及疲劳强度，可采用表面淬火。灰铸铁及球铁铸件均可进行表面淬火。一般采用高(中) 频感应加热表面淬火和电接触表面淬火。
7.化学热处理
对于要求表面耐磨或抗氧化、耐腐蚀的铸件，可以采用类似于钢的化学热处理工艺，如气体软氯化、氯化、渗硼、渗硫等处理。
air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,air, keep house air fresh, cooling, moisture, reduce the body temperature of the chicken, which is a measure of the chicken house the first element of the environment. (1) the parameters: ventilation in summer peak demand calculations, 4~5 cubic metres per kilogram of body weight per hour, harmful gas concentration does not exceed 20ppm ammonia, hydrogen sulfide, l0ppm, co 0.15%. (2) ventilation natural ventilation and mechanical ... 5. thermal insulation roof cold season is the region of greatest heat loss, are also hot towel sunlight than any other region, so the roof insulation is the most important region, followed by the walls, if open sheds to make doors and Windows switches freely, and seal well. On most of the walls and roof insulation must be taken or equivalent devices, thermal insulation materials require higher thermal resistance, good thermal insulation properties, and thicken the North wall must also be taken of thickness and measures such as roof and ceiling canopy. In places with more rain, due the eaves of roofs on both sides extending outward. Pheasants (pheasants) farm building (a) site choose pheasant fields should be selected gaozao terrain, sand texture, well drained, slightly to the South of terrain. Mountain areas should be selected under the sunny, spacious, ventilation, sunshine, where the drainage is good. Pheasant farms should be built in a quiet, safe place, away from residential areas, factories, the main traffic artery, but taking into account feed, transportation problems. A clean water source, water is not contaminated. To have a reliable power supply, not only to maintain normal lighting,
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