金属热处理外文及翻译

湖南工院

毕业设计(论文)外文翻译

外文题目Heat treatment of metal

译文题目金属热处理

系部机械工程系

专业班级机械设计制造及其自动化

机本0807班

学生姓名曹然

指导教师陈平、邓兴贵

完成时间2012-05

原文

Heat treatment of metal

The generally accepted definition for heat treating metals and metal alloys is “heating and cooling a solid metal or alloy in a way so as to obtain specific conditions or properties.”Heating for the sole purpose of hot working (as in forging operations) is excluded from this definition．Likewise，the types of heat treatment that are sometimes used for products such as glass or plastics are also excluded from coverage by this definition．

Transformation Curves

The basis for heat treatment is the time-temperature-transformation curves or TTT curves where，in a single diagram all the three parameters are plotted．Because of the shape of the curves，they are also sometimes called C-curves or S-curves．

To plot TTT curves，the particular steel is held at a given temperature and the structure is examined at predetermined intervals to record the amount of transformation taken place．It is known that the eutectoid steel (T80) under equilibrium conditions contains，all austenite above 723℃，whereas below，it is the pearlite．To form pearlite，the carbon atoms should diffuse to form cementite．The diffusion being a rate process，would require sufficient time for complete transformation of austenite to pearlite．From different samples，it is possible to note the amount of the transformation taking place at any temperature．These points are then plotted on a graph with time and temperature as the axes．Through these points，transformation curves can be plotted as shown in Fig.1 for eutectoid steel．The curve at extreme left represents the time required for the transformation of austenite to pearlite to start at any given temperature．Similarly，the curve at extreme right represents the time required for completing the transformation．Between the two curves are the points representing partial transformation. The horizontal lines Ms and Mf represent the start and finish of martensitic transformation.

Classification of Heat Treating Processes

In some instances，heat treatment procedures are clear-cut in terms of technique and application．whereas in other instances，descriptions or simple explanations are insufficient because the same technique frequently may be used to obtain different objectives．For example, stress relieving and tempering are often accomplished with the same equipment and by use of identical time and temperature cycles．The objectives，however，are different for the two processes．

The following descriptions of the principal heat treating processes are generally arranged according to their interrelationships．

Normalizing consists of heating a ferrous alloy to a suitable temperature (usually 50°F to 100°F or 28℃to 56℃) above its specific upper transformation temperature．This is followed by cooling in still air to at least some temperature well below its transformation temperature range．For low-carbon steels, the resulting structure and properties are the same as those achieved by full annealing；for most ferrous alloys, normalizing and annealing are not synonymous.

Normalizing usually is used as a conditioning treatment, notably for refining the grains of steels that have been subjected to high temperatures for forging or other hot working operations. The normalizing process usually is succeeded by another heat treating operation such as austenitizing for hardening, annealing, or tempering.

Annealing is a generic term denoting a heat treatment that consists of heating to and holding at a suitable temperature followed by cooling at a suitable rate. It is used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. The purpose of such changes may be, but is not confined to, improvement of machinability, facilitation of cold work (known as in-process annealing), improvement of mechanical or electrical properties, or to increase dimensional stability. When applied solely to relive stresses, it commonly is called stress-relief annealing, synonymous with stress relieving.

When the term “annealing”is applied to ferrous alloys without qualification, full annealing is applied. This is achieved by heating above the alloy’s transformation temperature, then applying a cooling cycle which provides maximum softness. This cycle may vary widely, depending on composition and characteristics of the specific alloy.

Quenching is a rapid cooling of a steel or alloy from the austenitizing temperature by immersing the work piece in a liquid or gaseous medium. Quenching medium commonly used include water, 5% brine, 5% caustic in an aqueous solution, oil, polymer solutions, or gas (usually air or nitrogen).

Selection of a quenching medium depends largely on the hardenability of material and the mass of the material being treating (principally section thickness).

The cooling capabilities of the above-listed quenching media vary greatly. In selecting a quenching medium, it is best to avoid a solution that has more cooling power than is needed to achieve the results, thus minimizing the possibility of cracking and warp of the parts being treated. Modifications of the term quenching include direct quenching, fog quenching, hot quenching, interrupted quenching, selective quenching, spray quenching, and time quenching.

Tempering. In heat treating of ferrous alloys, tempering consists of reheating the austenitized and quench-hardened steel or iron to some preselected temperature that is below the lower transformation temperature (generally below 1300 ℃or 705 ℃). Tempering offers a means of obtaining various combinations of mechanical properties. Tempering temperatures used for hardened steels are often no higher than 300 ℃(150 ℃). The term “tempering”should not be confused with either process annealing or stress relieving. Even though time and temperature cycles for the three processes may be the same, the conditions of the materials being processed and the objectives may be different.

Stress relieving. Like tempering, stress relieving is always done by heating to some temperature below the lower transformation temperature for steels and irons. For nonferrous metals, the temperature may vary from slightly above room temperature to several hundred degrees, depending on the alloy and the amount of stress relief that is desired.

The primary purpose of stress relieving is to relieve stresses that have been imparted to the workpiece from such processes as forming, rolling, machining or welding. The usual procedure is to heat workpiece to the pre-established temperature long enough to reduce the residual stresses (this is a time-and temperature-dependent operation) to an acceptable level; this is followed by cooling at a relatively slow rate to avoid creation of new stresses.

The generally accepted definition for heat treating metals and metal alloys is “heating and cooling a solid metal or alloy in a way so as to obtain specific conditions or properties.”Heating for the sole purpose of hot working (as in forging operations) is excluded from this definition．Likewise，the types of heat treatment that are sometimes used for products such as glass or plastics are also excluded from coverage by this definition．

Transformation Curves

The basis for heat treatment is the time-temperature-transformation curves or TTT curves where，in a single diagram all the three parameters are plotted．Because of the shape of the curves，they are also sometimes called C-curves or S-curves．

To plot TTT curves，the particular steel is held at a given temperature and the structure is examined at predetermined intervals to record the amount of transformation taken place．It is known that the eutectoid steel (T80) under equilibrium conditions contains，all austenite above 723℃，whereas below，it is pearlite．To form pearlite，the carbon atoms should diffuse to form cementite．The diffusion being a rate process，would require sufficient time for complete transformation of austenite to pearlite．From different samples，it is possible to note the amount of the transformation taking place at any temperature．These points are then plotted on a graph with time and temperature as the

axes．Through these points，transformation curves can be plotted as shown in Fig.1 for eutectoid steel．The curve at extreme left represents the time required for the transformation of austenite to pearlite to start at any given temperature．Similarly，the curve at extreme right represents the time required for completing the transformation．Between the two curves are the points representing partial transformation. The horizontal lines Ms and Mf represent the start and finish of martensitic transformation.

Classification of Heat Treating Processes

In some instances，heat treatment procedures are clear-cut in terms of technique and application．whereas in other instances，descriptions or simple explanations are insufficient because the same technique frequently may be used to obtain different objectives．For example, stress relieving and tempering are often accomplished with the same equipment and by use of identical time and temperature cycles．The objectives，however，are different for the two processes．The following descriptions of the principal heat treating processes are generally arranged according to their interrelationships．

Normalizing consists of heating a ferrous alloy to a suitable temperature (usually 50°F to 100°F or 28℃to 56℃) above its specific upper transformation temperature．This is followed by cooling in still air to at least some temperature well below its transformation temperature range．For low-carbon steels, the resulting structure and properties are the same as those achieved by full annealing；for most ferrous alloys, normalizing and annealing are not synonymous.

Normalizing usually is used as a conditioning treatment, notably for refining the grains of steels that have been subjected to high temperatures for forging or other hot working operations. The normalizing process usually is succeeded by another heat treating operation such as austenitizing for hardening, annealing, or tempering.

Annealing is a generic term denoting a heat treatment that consists of heating to and holding at a suitable temperature followed by cooling at a suitable rate. It is used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. The purpose of such changes may be, but is not confined to, improvement of machinability, facilitation of cold work (known as in-process annealing), improvement of mechanical or electrical properties, or to increase dimensional stability. When applied solely to relive stresses, it commonly is called stress-relief annealing, synonymous with stress relieving.

When the term “annealing”is applied to ferrous alloys without qualification, full annealing is applied. This is achieved by heating above the alloy’s transformation temperature, then applying a

cooling cycle which provides maximum softness. This cycle may vary widely, depending on composition and characteristics of the specific alloy.

Quenching is a rapid cooling of a steel or alloy from the austenitizing temperature by immersing the workpiece in a liquid or gaseous medium. Quenching medium commonly used include water, 5% brine, 5% caustic in an aqueous solution, oil, polymer solutions, or gas (usually air or nitrogen).

Selection of a quenching medium depends largely on the hardenability of material and the mass of the material being treating (principally section thickness).

The cooling capabilities of the above-listed quenching media vary greatly. In selecting a quenching medium, it is best to avoid a solution that has more cooling power than is needed to achieve the results, thus minimizing the possibility of cracking and warp of the parts being treated. Modifications of the term quenching include direct quenching, fog quenching, hot quenching, interrupted quenching, selective quenching, spray quenching, and time quenching.

Tempering. In heat treating of ferrous alloys, tempering consists of reheating the austenitized and quench-hardened steel or iron to some preselected temperature that is below the lower transformation temperature (generally below 1300 ℃or 705 ℃). Tempering offers a means of obtaining various combinations of mechanical properties. Tempering temperatures used for hardened steels are often no higher than 300 ℃(150 ℃). The term “tempering”should not be confused with either process annealing or stress relieving. Even though time and temperature cycles for the three processes may be the same, the conditions of the materials being processed and the objectives may be different.

Stress relieving. Like tempering, stress relieving is always done by heating to some temperature below the lower transformation temperature for steels and irons. For nonferrous metals, the temperature may vary from slightly above room temperature to several hundred degrees, depending on the alloy and the amount of stress relief that is desired.

The primary purpose of stress relieving is to relieve stresses that have been imparted to the workpiece from such processes as forming, rolling, machining or welding. The usual procedure is to heat workpiece to the pre-established temperature long enough to reduce the residual stresses (this is a time-and temperature-dependent operation) to an acceptable level; this is followed by cooling at a relatively slow rate to avoid creation of new stresses.

The generally accepted definition for heat treating metals and metal alloys is “heating and cooling a solid metal or alloy in a way so as to obtain specific conditions or properties.”Heating for the sole purpose of hot working (as in forging operations) is excluded from this definition．Likewise，

the types of heat treatment that are sometimes used for products such as glass or plastics are also excluded from coverage by this definition．

Transformation Curves

The basis for heat treatment is the time-temperature-transformation curves or TTT curves where，in a single diagram all the three parameters are plotted．Because of the shape of the curves，they are also sometimes called C-curves or S-curves．

To plot TTT curves，the particular steel is held at a given temperature and the structure is examined at predetermined intervals to record the amount of transformation taken place．It is known that the eutectoid steel (T80) under equilibrium conditions contains，all austenite above 723℃，whereas below，it is pearlite．To form pearlite，the carbon atoms should diffuse to form cementite．The diffusion being a rate process，would require sufficient time for complete transformation of austenite to pearlite．From different samples，it is possible to note the amount of the transformation taking place at any temperature．These points are then plotted on a graph with time and temperature as the axes．Through these points，transformation curves can be plotted as shown in Fig.1 for eutectoid steel．The curve at extreme left represents the time required for the transformation of austenite to pearlite to start at any given temperature．Similarly，the curve at extreme right represents the time required for completing the transformation．Between the two curves are the points representing partial transformation. The horizontal lines Ms and Mf represent the start and finish of martensitic transformation.

Classification of Heat Treating Processes

In some instances，heat treatment procedures are clear-cut in terms of technique and application．whereas in other instances，descriptions or simple explanations are insufficient because the same technique frequently may be used to obtain different objectives．For example, stress relieving and tempering are often accomplished with the same equipment and by use of identical time and temperature cycles．The objectives，however，are different for the two processes．The following descriptions of the principal heat treating processes are generally arranged according to their interrelationships．

Normalizing consists of heating a ferrous alloy to a suitable temperature (usually 50°F to 100°F or 28℃to 56℃) above its specific upper transformation temperature．This is followed by cooling in still air to at least some temperature well below its transformation temperature range．For low-carbon steels, the resulting structure and properties are the same as those achieved by full annealing；for most ferrous alloys, normalizing and annealing are not synonymous.

Normalizing usually is used as a conditioning treatment, notably for refining the grains of steels that have been subjected to high temperatures for forging or other hot working operations. The normalizing process usually is succeeded by another heat treating operation such as austenitizing for hardening, annealing, or tempering.

Annealing is a generic term denoting a heat treatment that consists of heating to and holding at a suitable temperature followed by cooling at a suitable rate. It is used primarily to soften metallic materials, but also to simultaneously produce desired changes in other properties or in microstructure. The purpose of such changes may be, but is not confined to, improvement of machinability, facilitation of cold work (known as in-process annealing), improvement of mechanical or electrical properties, or to increase dimensional stability. When applied solely to relive stresses, it commonly is called stress-relief annealing, synonymous with stress relieving.

When the term “annealing”is applied to ferrous alloys without qualification, full annealing is applied. This is achieved by heating above the alloy’s transformation temperature, then applying a cooling cycle which provides maximum softness. This cycle may vary widely, depending on composition and characteristics of the specific alloy.

Quenching is a rapid cooling of a steel or alloy from the austenitizing temperature by immersing the workpiece in a liquid or gaseous medium. Quenching medium commonly used include water, 5% brine, 5% caustic in an aqueous solution, oil, polymer solutions, or gas (usually air or nitrogen).

Selection of a quenching medium depends largely on the hardenability of material and the mass of the material being treating (principally section thickness).

The cooling capabilities of the above-listed quenching media vary greatly. In selecting a quenching medium, it is best to avoid a solution that has more cooling power than is needed to achieve the results, thus minimizing the possibility of cracking and warp of the parts being treated. Modifications of the term quenching include direct quenching, fog quenching, hot quenching, interrupted quenching, selective quenching, spray quenching, and time quenching.

Tempering. In heat treating of ferrous alloys, tempering consists of reheating the austenitized and quench-hardened steel or iron to some preselected temperature that is below the lower transformation temperature (generally below 1300 ℃or 705 ℃). Tempering offers a means of obtaining various combinations of mechanical properties. Tempering temperatures used for hardened steels are often no higher than 300 oF (150 ℃). The term “tempering”should not be confused with either process annealing or stress relieving. Even though time and temperature cycles for the three processes may be the same, the conditions of the materials being processed and the objectives may be different.

Stress relieving. Like tempering, stress relieving is always done by heating to some temperature below the lower transformation temperature for steels and irons. For nonferrous metals, the temperature may vary from slightly above room temperature to several hundred degrees, depending on the alloy and the amount of stress relief that is desired.

The primary purpose of stress relieving is to relieve stresses that have been imparted to the workpiece from such processes as forming, rolling, machining or welding. The usual procedure is to heat workpiece to the pre-established temperature long enough to reduce the residual stresses (this is a time-and temperature-dependent operation) to an acceptable level; this is followed by cooling at a relatively slow rate to avoid creation of new stresses.

金属热处理

对于热处理金属和金属合金普遍接受的定义是“加热和冷却的方式了坚实的金属或合金，以获得特定条件或属性为唯一目的。”暖气热加工（如锻造操作）被从这个定义排除.例如，热处理的是某些产品，如玻璃或塑料制品使用的类型也被排除在这个定义范围。

转变曲线

对热治疗的基础是时间温度曲线或倾斜试验曲线改造的地方，在一个图所有三个参数是该曲线的形状。因为，他们有时也称为C -曲线或S -曲线。

TTT治疗绘制曲线，特别是钢材举行一个给定的温度和结构是在预定的时间间隔检查，以记录转换采取量是已知的共析钢在平衡条件下（T80）包含，以上723奥氏体℃，而下面，它是珠光体，碳原子扩散，形成应该是一个扩散率的过程中，将需要完成的奥氏体转变为不同的样本足够的时间，有可能要注意转换的数额采取任何点进行，然后在一个随时间和温度的这些点绘制图表，曲线可以绘制转型所示的共析制成，曲线图极端离开代表着奥氏体转变所需的时间珠光体开始在任何温度.相似地，在极右曲线代表的完成的两条曲线的点代表局部改造所需的时间。横线代表女士和MF的开始和完成马氏体相变。

分类处理过程中的热

在某些情况下，热处理程序是明确的技术条款和应用.否则在其他情况下，简单的解释说明或削减是不够的，因为同样的方法经常可以用来获得不同物体.例如，压力正在缓解，回火往往具有相同的设备和相同的时间和温度使用旋回目标完成，然而，对于不同的两个过程。

处理过程中的主要热下面的说明，一般安排根据它们的相互关系。

规范包括由静止空气冷却到一定温度至少远低于遵循有色合金加热到适当温度高于其特定的上转换温度.This（通常为50 ℃到100 ℃或28℃至56℃）其相变温度range.For低碳钢，由此产生的结构和性质是完全退火所取得的相同;对大多数铁合金，正火，退火不是同义词。

规范通常被用作调理治疗，特别是用于提炼已受到锻造或其他热工操作，高温钢的晶粒。正火过程通常是成功的另一个热处理操作，如奥氏体的硬化，退火，回火等方式。

退火是一种通用术语表示一个热处理的加热并在合适的速率通过在适当的温度冷却后举行组成。它主要用于金属材料软化，但也同时产生其他财产或组织期望的变化。这种变化的目的可能是，但不仅限于，改善可加工性，促进工作的冷（如进程退火已知），机械或电气性能的提高，或增加尺寸稳定性。当应用仅重温讲，它通常被称为压力缓解压力救济退火，同义。

当术语“退火”是适用于无资格铁合金，完全退火应用。这是通过加热上述合金的相变温度，然后涂上冷却循环，提供了最大的柔软性。这个周期可能有很大的不同，这取决于具体的组成和合金的特点。

淬火是一个从奥氏体钢或高温合金，浸在液体或气体介质中的工件快速冷却。淬火中常用的包括水，5％盐水，水溶液，油，聚合物溶液或气体（通常是空气或氮气）5％烧碱。

淬火介质的选择很大程度上取决于材料的淬透性和正在治疗（主要部分厚度）材料的质量。

上述淬火介质的冷却能力相差很大。在选择淬火介质，它是最好的解决方案，以避免有更多的冷却能力比需要达到的结果，从而减少了开裂和变形的部分正在接

受治疗的可能性。一词的修改包括直接淬火淬火，淬火雾，热淬火，淬火中断，选择性淬火，喷雾淬火，淬火和时间。

回火。在黑色金属热处理合金，回火加热炉的奥氏体和淬火硬化钢或铁的一些预选的温度低于下转变温度（一般低于1300℃或705℃）组成。回火提供了一个获取力学性能的各种组合方式。为硬化钢回火温度通常采用不高于300℃（150℃）。术语“回火”不应该被混淆或者消除应力退火或过程。尽管这三个过程的时间和温度周期可能是相同的，这些材料被处理的条件和目标可能会有所不同。

消除应力。像回火，消除应力总是被加热到下面的一些钢材和铁的转变温度低的温度进行。有色金属，气温可能会有所不同温度高于室温稍微几百度，取决于合金和缓解压力的数量是需要的。

纾缓压力的主要目的是减轻压力已经从这些进程传授到工件的成形，轧制，加工或焊接。通常的程序是工件加热到预定的温度足够长的时间，以减少残余应力（这是一个时间和温度相关的操作）到一个可接受的水平，这是由处于相对缓慢的速度冷却，以避免创造遵循新的压力。