機械工程专业英语课本翻译.pptVIP

机械专业外语1（设计）;绪论;教学内容;（续前页）教学章节;学习本课程注意事项;Lesson 1 Ferrous metals and Their Use ;Paragraph Analysis;Metals consisting of iron combined with some other elements are known as ferrous metals; all the other metals are called nonferrous metals. 由铁和一些其他元素构成的金属被称为黑色金属；所有其他的金属被称为有色金属。 Ferrous metals include plain-carbon steels, alloy and tool steels, stainless steels, and cast irons. 黑色金属包括普通碳钢、合金钢、工具钢、不锈钢和铸铁。 ★ plain-carbon steels普通碳钢, alloy and tool steels,合金钢、工具钢、 stainless steels,不锈钢and cast irons铸铁;These groups of ferrous alloys have a wide variety of characteristics and applications. 这些黑色金属合金具有各种特性且应用广泛;Paragraph 2;Low carbon steel containing from 0.02 to 0.25 percent carbon, and they are very soft and can be used for bolts and for machine parts that do not need strength. 低碳钢含碳量0.02-0.25%，它们很软，能够用于螺栓和不需要强度的机械零件。 Medium carbon steel containing from 0.25 to 0.6 percent carbon which is a better grade and stronger than low carbon steel. 中碳钢含碳量0.25-0.6%，相比低碳钢品质更好，强度更高。; High carbon steel containing from 0.6 to 2.11 percent carbon, these steel is sometimes called “ tool steel ”. 高碳钢含碳量0.6-2.11%，这些钢有时被称为工具钢。 They obtain high hardness by a quench and temper heat treatment. 它们通过淬火和回火热处理获得高硬度。 Their applications include cutting tools in machining operations, dies for die casting, forming dies, and other in which a combination of high strength hardness, toughness, or temperature resistance is needed. 它们的应用包括机加工中的切削刀具、压铸中的模具、成型模以及其他，在其中，和具有高强度、硬度、刚性或耐热性的元素的结合是必须的。;淬火;回火;Paragraph 3;There are four categories of stainless based on crystal structure and strengthing mechanism. They are the ferritic stainless steel, martensitic stainless steel, austenitic stainless steels and precipitation hardening stainless steels. 根据不锈钢的组织和力学性能来分，不锈钢可以分为四种：铁素体不锈钢，奥氏体不锈钢，马氏体不锈钢和沉淀硬化不锈钢。;Paragraph 4;面心立方晶格;体心立方晶格;Without the high nickel content, the bcc structure is stable, as seen in the ferritic stainless steels. 如果没有高的镍含量，体心立方结构是稳定的，如铁素体不锈钢。 For many applications not requiring the high