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1、,English on Mechanical Engineering Lesson 1 Engineering Material,Text Cast iron Cast iron is a general applied to a wide range of iron-carbon-silicon alloys in combination with smaller percentages of several other elements. It is an iron containing so much carbon, or its equivalent, that it is not m
2、alleable. Quite obviously, cast iron has a wide range of properties, since small percentage variations of its elements may cause considerable change. Cast iron should not be thought of as a metal containing a single element, but rather, as one having in its composition at least six-elements. All cas
3、t irons contain iron, carbon silicon, manganese, phosphorous and sulfur. Alloy cast iron has still other elements, which should not be thought of as impurities, for they all have important effects on the physical properties. Pure iron, known as ferrite, is very soft and has few uses in industrial wo
4、rk.,All desirable properties, such as strength, hardness, and machinability, are controlled by regulating the elements other than ferrite in the cast iron. The cast iron family includes gray, ductile (also called nodular), white, malleable, and, high-alloy irons. Gray iron is itself a family of cast
5、ing alloys, and is the most widely used, with an annual production several times the total for all other metals cast. A relatively new type of cast iron is ductile iron. As its name implies, ductile iron offers more ductility than gray iron, plus higher strength.,Text,Steels Due to their lower cost,
6、 the majority of steels used in industrial work are plain carbon steels. Plain carbon steels have various amounts of carbon without substantial amounts of other alloying elements. These are classified into three general categories: low, medium and high carbon steels. Each class contains carbon as fo
7、llowing: Low-carbon has up to 0.20%. Medium-carbon has between 0.20% and 0.50%. High-carbon has more than 0.50%.,Text,Low-carbon steels are the softest and most ductile of the three. Their properties are not greatly influenced by heat treatment. Medium-carbon steels, the most common, are harder than
8、 low-carbon steels; heat-treatment increases their ductility and impact resistance. Because of the higher carbon content, high-carbon steels offer the highest strength and hardness. They are used where wear and abrasion-resistance are necessary.,Text,When other alloying elements, in addition to carb
9、on, are added in substantial amounts the steels are called alloy steels. The two main categories are low alloy and high alloy steels. Low alloy cast steels have a carbon content 0.45% or less, and total alloying elements of less than 8%. Because of the favorable effects of these elements, low-alloyi
10、ng steels develop higher strength through heat treatment. As contrasted to low-alloy steels, high-alloy steels have alloying elements more than 8%.,Text,Types of high-alloy steels: Chromium steel: chromium from 12% 30%. Chromium-nickel steel: chromium from 18% 32% and nickel from 8% 20%. Nickel-chro
11、mium steel: nickel from 33% 41% and chromium from 13% 21%. High-nickel-chromium steel: nickel from 58% 68% and chromium from 10% 19%. -end,1、Engineering Material 工程材料 engineering n.工程(学) engineer n.工程师, 技师 material n.材料, 原料, 物资 adj.物质的, 2、Element n. 元素, 要素, 成分, 元件, 自然环境 3、Equivalent adj.相等的, 相当的 n.
12、相等物，当量、等值的 4、property n. 性能、财产,性质, 特性 5、composition n. 合成物，复合，写作 6、impurity n.杂质, 混杂物, 不洁, 不纯 7、strength n. 强度，力量, 兵力, 浓度 8、hardness n. 硬度, 硬, 艰难, 难度 9、machinability n.加工性能、切削性能 10、category n.种类, 别, 逻范畴,Words and Expressions:,11、heat treatment n.热处理 12、impact resistance 抗冲击性； impact 碰撞、冲击力； resistan
13、ce 阻力 ；R:电阻 13、wear-resistance 耐用性、耐磨性、磨损阻力 wear v. 磨损、损耗；( out) 磨损, 用旧 vt.穿, 戴 14、abrasion-resistance 耐磨性、抗磨力（性） 15、combination n. 结合, 联合, 合并,集成,组合; crystal combination合晶 missile-cruiser combination配有导弹的巡洋舰 16、regular vt. 调节、规定 adj.规则的, 经常的,合格的, 定期的 n.正规军, 正式队员 17、annual adj.一年一次的, 每年的, 一年生的 n.一年生植
14、物, 年刊, 年鉴 annual production 年产量,1, general term 总的术语、广义术语 2, a wide range of 广大的范围、广泛的 3, in combination with 与。结合、联合 4, percentage n.百分数, 百分率 百分比percent符号，up to：以下 如：up to 0.20% 5， variation n.变化, 变异 various adj.各种各样的 6， but rather 而是，反而是 7， control v.控制 NCNumerical Control, 数字控制 CNC Computerized N
15、umerical Control 计算机数字控制,Technical phrases:,8， other than 而不是 9， due to adv.由于, 应归于 10， substantial amounts of 足够量的、一定量的 substantial adj. 充实的，坚固的 amount n.数量 vi.(to) 总计, 等于 11， classify into vt.分类, 分等 12， in addition to adv.除.之外 13， contrast to 使与.对比, 和.形成对照,Technical phrases:,Specialized term: 1、me
16、tal n. 金属 2、ferrite n.化(正)铁酸盐, 铁、铁元素、(冶)铁素体 3、pure iron n. 纯铁 pig iron生铁 wrought iron熟铁, 锻铁 4、white iron n. 白口铁 5、iron-carbon-silicon alloys 铁碳硅合金 6、cast iron n.铸铁, 锻铁 （5 kinds） 7、grey iron n. 灰口铸铁 Gray =grey 灰色的; 8、nodular-iron n. 球墨铸铁 nodular adj.结节状的、瘤状的； 9、ductile-iron n. 可锻铸铁 ductile adj.可延展、可锻的、柔软的 Ductility n. 延展性 10、malleable iron n. 可锻铸铁,11、high alloy iron n. 高合金铸铁 carbon n.化碳(元素符号C), (一张)复写纸 silicon n.
