2. 江西制造职业技术学院 江西制造职业技术学院 English for Mechanical Engineering Reading Comprehension 机械专业英语阅读

3. Unit One : The Foundation of Metalworking

4. Passage One Properties of Metals and Heat Treatment of Steel

5. Learning Objectives To understand the whole passage. To list the properties of metals in English. ★ ★ ★ To know different kinds of heat treatment of steel.

6. Training Target In the part, our target is to train your reading speed. You should pay more attention to “word group”. Treating a group of words as a whole unit is a short cut to save your time.

7. Teaching Procedures Step D: Assignment Step C: Structural Analyzing Step B: Passage Understanding Step A: Lead in

8. Lead-in: discussion How many kinds of metals’ properties do you know ? How many kinds of heat treatment of steel do you know?

9. Lead- in: discussion 柔性 刚性 硬度 强度 弹性 可塑性 循环使用 韧性

10. Lead- in: discussion 柔性 刚性 硬度 强度 弹性 可塑性 循环使用 韧性 strength hardness toughness ductility plasticity reuse recycling elasticity

11. Lead- in: discussion 柔性 ductility 刚性 toughness 硬度 hardness 强度 strength 弹性 plasticity 可塑性 plasticity 循环使用 recycling/ reusing 韧性 toughness

12. Lead- in: discussion Four types of heat treatment: 淬火 hardening 退火 annealing 回火 tempering 正火 normalizing

13. 1. How many categories can the properties of metal be classified? 2. What are they? Passage understanding Scan the whole passage and try to answer the following questions.

14. The properties of metal can be classified into three categories: chemical properties, physical properties, and mechanical properties. Passage understanding

15. Chemical properties: all metals are used in some types of environment. They react with gases, liquids and solids thus corrosion appears. Oxidation, electrochemical corrosion and water absorption all belong to chemical properties. Passage understanding 气体， 液体， 固体 吸水性

16. Physical properties include electrical, magnetic, optical, thermal behavior and density and so on. The physical properties depend both on structure and processing of the metal. Passage understanding

17. The mechanical properties describe metal’s ability to resist the application of mechanical forces and loads. Here we will emphasize the primary mechanical properties of metals. In understanding the related areas of metalworking and methods used today, the mechanical properties of metals are of the utmost importance. Passage understanding

18. category n. 种类，类别，范畴 e.g. There are different categories of books in a library. e.g. A category created for purposes of competition, as in boxing. e.g. How can a scientific category have its derivatives? Words and expressions

19. kind 指性质相同，而且特征很相似，足以归为一类的人或东西。 sort 普 通用词，文体较 kind 随便，指对人或事物进行的大概分类，有时含贬义。 type 指客观界限比较清楚，有相同本质特点的同类事物，或指大致相似的同类事物。 class 正式用词，指门类，种类或优劣等级，用于指动植物的分类时，表示 ” 纲 “ 。 classification 指根据已经确定的类型对某一事物做鉴别和归类。 category 书面用词，特指有确切定义的群体。 species 书面用词，单 复数同行。指生物分类上的种类。 variety 强调有各自的特点，形 式不同，品质不同的种类。 Words and expressions 词义辨析 kind,sort, type, class, classification, category, species, variety 这些词均有 “ 种，类，类型 ” 之意。

20. corrosion n. 侵蚀，腐蚀，锈蚀 e.g. They are sprayed with oil to prevent corrosion. Words and expressions absorption n. 吸收，全神贯注，合并 e.g. Exercise can promote absorption of nutrients by the body. resist v. 抵制，抵抗，反抗，忍住 e.g. Many young people could not resist the spiritual pollution. e.g. I want a kind of glass dish that resists heat.

21. be+ of+ n.= be+ adj. Words and expressions e.g. The mechanical properties of metals are of the utmost importance. =The mechanical properties of metals are utmost important. e.g. The document he gave to you is of great value. = The document he gave to you is greatly valuable. e.g. The scene of this village is of beauty. =The scene of this village is very beautiful.

22. Passage understanding Properties of metals: Among various type of materials used in engineering practice metals are commonly used. Metals have many properties that distinguish them from other materials, such as strength, hardness, elasticity, ductility and toughness.

23. Passage understanding Properties of metals: 状语： Among various type of materials used in engineering practice 主语： metals 谓语： are commonly used.

24. Passage understanding Properties of metals: The most important of these properties is strength, or the ability to support weight without bending or breaking. This property combined with toughness, or ability to bend without breaking, is important.

25. Passage understanding Properties of metals: Metals also have advantages regarding resistance to corrosion. They are responsive to heat treatment. Engineers must know the properties of metal and how they can be worked so that they can select the best and most economical metals when needed.

26. Passage understanding Properties of metals: 主语： Engineers 谓语： must know 宾语： the properties of metal and how they can be worked 结果状语从句： so that they can select the best and most economical metals when needed.

27. Passage understanding Properties of metals: The propertied of metal can be classified into three categories: chemical properties, physical properties, and mechanical properties.

28. Passage understanding Properties of metals: Chemical properties: all metals are used in some types of environment. They react with gases, liquids and solids thus corrosion appears. Oxidation, electrochemical corrosion and water absorption all belong to chemical properties.

29. Passage understanding Properties of metals: Physical properties: include electrical, magnetic, optical, thermal behavior and density and so on. The physical properties depend both on structure and processing of the metal.

30. Passage understanding Properties of metals: The mechanical properties describe metal’s ability to resist the application of mechanical forces and loads. Here we will emphasize the primary mechanical properties of metals. In understanding the related areas of metalworking and methods used today, the mechanical properties of metals are of the utmost importance.

31. Passage understanding Properties of metals: 状语： In understanding the related areas of metalworking and methods used today 主语： the mechanical properties of metals 系表结构： are of the utmost importance.

32. Passage understanding Heat treatment of steel: Heat treatment is a part of metallurgy. It changes the structures of metals by the application of heat and obtains the desired mechanical properties. The main kinds of heat treatment use in practice are: (1) hardening; (2) tempering; (3) annealing; (4) normalizing.

33. Passage understanding Heat treatment of steel: Hardening: In any heat-treating operation the rate of heating is very important. Heat flows from the exterior to the interior of steel at a definite maximum rate. If steel is heated too fast, the exterior of the part becomes hotter than the interior. A uniform structure is hard to obtain.

34. Passage understanding exterior 外部 interior 内部 export 出口 import 进口 external 外面 internal 内部，里面

35. Passage understanding Heat treatment of steel: The hardness that can be obtained from a given treatment depends upon the following three factors: 1.Quenching rate. 淬火速度 2. Carbon content. 含碳量 3. Work-piece size. 工件尺寸

36. Passage understanding Heat treatment of steel: Annealing: Annealing consists of heating steel slightly above its critical range and cooling very slowly. Annealing relieves internal stresses and strain caused by previous heat treatment, machining, or other cold- working processes.

37. Passage understanding Heat treatment of steel: There are three different types of annealing processes used in industry, (1) full annealing, (2) process annealing, (3) spheroid zing.

38. Passage understanding Heat treatment of steel: Normalizing: normalizing is a process used to relieve the internal stresses due to hot-working, cold-working, and machining. The process consists of heating steel slightly above the upper critical range 30C to 50C and cooling to room temperature after holding for a while.

39. Difficult Point The maximum degree of hardness obtainable in steel by direct hardening is determined largely by the carbon content. 主语 : the maximum degree of hardness 谓语 : is determined 定语 : Obtainable in steel by direct hardening 直接淬火后的钢所能获得的最大硬度在很大程度 上是由含碳量决定的。

40. Structural Analyzing Part One: Para 1-9: Properties of metals; Part Two: Para 10-20: Heat treatment of steel. How many main parts are there in this passage? hardening tempering annealing normalizing

41. exercises Translate the following words into English. 含碳量 退火 内应力 正火 热处理 机械加工性 冷加工 强度 热学的 临界温度 Carbon content annealing Internal stress normalizing Heat treatment machinability Cold working strength thermal Critical temperature

42. 江西制造职业技术学院