《模具专业英语》PPT课件.ppt

1、Unit one Lesson2 Heat Treatment of Tool Steels,教学目标及要求 1.掌握课文中有关热处理方面的专业词汇和专业术语； 2.结合热处理的相关专业知识阅读课文，提高翻译能力。 重点 1.有关热处理的专业词汇和专业术语； 2.翻译课文：热处理的原理; 热处理的类型; 热处理的步骤。 难句分析及翻译的基础知识 Part（） 翻译的基础知识简介 二、翻译的标准,教学思路设计 时间分配（共100min）： 1.讲解课文中的专业词汇和术语； 2.讲解课后生词、大声朗读； 3.翻译课文，注意穿插相关专业知识； 4.分析难点句型，讲解相关翻译基础知识； 5.学生答疑。

2、,Contents,Background Knowledge New Words and Phrased Text Analysis Questions Glossary of Terms Language Points & Translating Techniques Reading Materials Summary References,The Principles of Heat Treatment,Heat treatment consists of Heating-Up and Cooling-Down process. Heating up the steel will chan

3、ge the microstructure to Austenite. Cooling down the steel at different cooling rates will change the microstructure from Austenite to different structures correspondingly. Change in Microstructures result in change in mechanical properties.,Background Knowledge,By heat treatment, we can change the

4、mechanical properties of moulds and machine components to our desired state. For example, to harden the mould will increase strength and wear resistance resulting in longer mould life. To anneal a hard steel bar will soften it to a state good for machining. To normalize a steel bar will toughen it t

5、o a state good for impact.,New Words and Expressions,Terms： 1. Heat treating 热处理 normalize 正火 spheroidiz 球化处理 anneal 退火 harden 淬火 temper 回火 case harden 表面淬火 stress relieving 应力消除热处理 carburize 渗碳 quench-hardening 淬火硬化,New Words and Expressions,Terms： 2.Iron-carbon equilibrium diagram 铁碳平衡相图 ferrite 铁

6、素体 austenite 奥氏体 pearlite 珠光体 carbide 碳化物 bainite 贝氏体 martensite 马氏体 liquid 液态 delta-iron -铁 alpha-iron -铁 gamma-iron -铁,Iron-carbon equilibrium diagram,Time-temperature transformation (TTT) diagrams,A Continuous cooling transformation (CCT) curve compared to TTT diagram,亚微观的；普通显微镜下看不出来的,Tempering,D

7、uring tempering, martensite undergoes a transformation process from that of carbon atoms supersaturated in iron to a structure termed tempered martensite which consists of highly dispersed submicroscopic carbide particles in a ferrite matrix. The extent of increase in ductility hence toughness and t

8、he corresponding reduction in hardness and strength is a function of tempering temperature and time.,回火；调和,Annealing,If a steel bar is cooled slowly in a furnace from a temperature above its upper critical temperature to a temperature below the lower critical temperature, the structure of the steel

9、will become ferrite and cementite again. This steel consists of a somewhat coarser grain structure that is low in strength, high in ductile and soft. This process of heat treatment is called Annealing.,退火，缓冷，韧化,正火,Normalizing,However, instead of cooling in furnace as described above, the steel is ta

10、ken out from the furnace and cooled in still air, it is termed Normalizing. A normalized steel bar possesses higher strength and toughness than its annealed counterpart.,对应物，配对物,Quench-Hardening,If a steel bar is rapidly cooled from its upper critical temperature by plunging it into a coolant such a

11、s water or oil (termed quenching), the effect is to transform the austenite into a structure called martensite. Martensite is a very hard, but brittle constituent of steel. For steels having a carbon content less than 0.8%, a temperature at between 30 deg C to 50 deg C above the upper critical tempe

12、rature (723 deg C) is used for quenching and the resulting structure comprises martensite and ferrite.,The Heat Treatment Process,Basically, Heat Treatment just consists of heating up and cooling down process. These process can be further divided into four steps.,One Step1 Construction of Time-Tempe

13、rature-Transformation Diagram (TTT)and Continuous Cooling Transformations Diagram (CCT) TTT Diagrams - can be quite useful in determining the kinetics of transformation and the nature of the products. The curve shows the time required to complete the transformation at that temperature.,One Step2,CCT

14、 Diagrams - Although the TTT diagrams can provide useful information about the structures obtained through non-equilibrium thermal processing, they are not rigorously applicable to engineering applications because the assumptions of instantaneous cooling from elevated temperature is far more realist

15、ic, and a diagram showing the results of continuous cooling at various rates would be far more useful.,Two Steps,The second step is a heating operation designed to produce an elevated temperature homogeneous single-phase solid solution. The heating should not exceed the eutectic temperature or there

16、 might be melting if a cored structure were present.,Three And Four Steps,After soaking to assure a uniform chemistry single phase, the alloy is cooled. The cooling rate of the alloy depends on the property of metal required. The heat treated material is then left for diffusion. Diffusion is necessa

17、ry to convert the unstable supersaturated solution into the stable structure.,Surface Hardening,For many engineering purposes it is desirable for parts to have a hard surface to resist wear and abrasion and the inner portion remains soft and tough to sustain impact loading. This depth of the hardene

18、d surface is normally from 0.0001 mm to a few mm depending on applications. These properties can be obtained by surface hardening which is generally divided into the following three types:,Gas carburizing,Nitriding Method,Principle of Induction Hardening,Questions,What process is used to remove the

19、internal stresses created during a hardening operation? What heat treating process makes the metallic carbides in a metal form into small rounded globules? What are the main purposes of heat treating? How many heat treating processes are involved in ferrous materials? ,Glossary of Terms,1Hardenabili

20、ty 淬透性 2hardenability curve 淬透性曲线 3hardening capacity 淬硬性（硬化能力） 4hardness profile 硬度分布（硬度梯度） 5heat treatment procedure 热处理规范 6heat treatment installation 热处理设备 7heat treatment furnace 热处理炉 8heat treatment cycle 热处理工艺周期 9heat time 加热时间 10 heat system 加热系统 11 heating up time 升温时间 12 heating curve 加热曲线

21、,13high temperature carburizing 高温渗碳 14high temperature tempering 高温回火 15isothermal transformation 等温转变 16isothermal annealing 等温退火 17interrupted ageing treatment 分级时效处理 18local heat treatment 局部热处理 19overheated structure 过热组织 20pack carburizing 固体渗碳 21oxynitrocarburizing 氧氮碳共渗 22partial annealing 不

22、完全退火 23spheroidized structure 球化组织 24recrystallization temperature 再结晶温度,Example 1: This combination of heating and controlled cooling determines not only the nature and distribution of the microconstituents, which in turn determine the properties, but also the grain size. （在热处理过程中），加热与冷却控制相结合的方法不仅决

23、定着材料中微观组织的分布和性质（进而决定了该材料的性能），而且也决定了材料内部晶粒的大小。 句中第一个and连接的是heating和controlled cooling，第二个and连接的是nature和distribution，而which in turn determine the properties为非限定性定语从句,修饰the nature and distribution。,Language Points & Translating Techniques,Example 2: With most of the mediumcarbon forging steels, alloyed

24、 and unalloyed, normalizing is highly recommended after forging and before machining to produce more homogeneous structures, and in most cases, improved machinability. 对于大多数中碳锻钢来说，不管它是否合金化，在锻造后或加工前通常推荐采用正火处理工艺，这样有利于形成更均匀的组织，并且在大多数情况下可改善材料的切削加工性能。 句首的介词with短语意为“对来说”；in most cases可译为“在大多数情况下”。,二、翻译的标准

25、 翻译的任务在于准确而完整地介绍原文的思想内容，使读者对原文的思想内容有正确的理解。然而，怎样才算是准确、完整的翻译呢？要解决这个问题，就需要有一个共同的翻译标准。 谈到翻译标准，不免要提到严复的“信、达、雅”。严复在他的一部译著的前言中提出了“信、达、雅”。“信”就是忠实原文，“达”就是表达清楚，“雅”即是文字文雅。后来，鲁迅先生在此基础上又提出了“信”和“顺”这两条标准。“信”和“顺”，即“忠实”、“通顺”，今天已成为公认的两条标准了。,Example 3:,“忠实”是指译文的思想内容必须忠实于原文，这一标准对科技英语尤为重要，因为科技作品的任务在于准确而系统地论述科学技术问题，它要求高度

26、的准确性，特别是对术语、定义、定理和结论的翻译更应重视。 然而，忠实原文并不是形式上保持原文，而是内容上保持原文。翻译时切忌逐字死译，这样会有损原意。请看例句： A roughing cut is usually to be followed by a fishing cut. 粗切削通常要被精切削跟随。 译文的毛病在于虽然词类或句子成分都与原文一致，保持了原文的形式，但却失去了原文的精神。若译成“粗切之后，通常还要精切”才算忠实原文。 翻译的第二条标准是“通顺”。“通顺”是指译文的语言形式必须符合汉语规范，翻译时要按照汉语的语法规律和习惯来遣词造句，做到通顺易懂。但要指出，“通顺”是在“忠实”的前提下，任何“顺而不信”都是不行的，属于乱译。,看下面一个例子： The foundation of the machine should not be constructed at a place of conspicuous temperature change, due to direct sunshine, excessive heat or vibration, or at a place contaminated with soil o