机械专业外语new1.ppt

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1、绪论,1.专业英语Special EnglishProfessional English2.基础英语Elementary English3.教学要求主要培养学生专业文献的阅读和翻译水平，掌握一定的专业词汇和专业术语，拓宽专业知识面，了解机械专业前沿的相关内容。,教学内容,1.教材机械工程专业英语中国电力出版社出版2.教学章节PART Mechanical Materials and Heat Treatment 1.Ferrous Metals and Their Use2.Nonferrous Metals4.Castings5.Forging7.Heat Treatment8.Engine

2、ering Material,（续前页）教学章节,PART II Mechanical Elements and Mechanisms1.Transmission2.Gear3.Belt Drive4.Coupling5.Bearing9.Properties of Hydraulic Fluids PART Mechanical Design 1.Mechanical Design,学习本课程注意事项,1.尊重原文专业文献较为严谨，因此翻译过程中不需要加入过多的修饰词语，不要主观随意添加2.注意语言习惯科技或专业英语常用被动语态,汉文多数情况下使用主动语态.翻译英文长句时要学会将从句分拆,必

3、要时运用转译技巧,Lesson 1 Ferrous metals and Their Use,Words and Expressions,Paragraph Analysis,Paragraph 1It is known that ferrous metals are very important in the world,and have the greatest importance for industry.众所周知黑色金属是非常重要的，对工业来说最为重要。More than 90%by weight of the metallic materials used by human bei

4、ngs are ferrous alloys.人类使用的90%以上的金属材料为黑色金属合金,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 stee

5、ls,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。,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,Carbon steels are the most common steels used in industry.碳钢是工业中最常使用的一种钢材。These eminently practical materials find applications from bal

6、l bearings to metal sheet formed into automobile bodies.这些实用材料被应用于从滚珠轴承到汽车车身的金属板。The properties of these steels depend only on the percentage of carbon they contain.这些钢的性质仅仅依赖于碳的含量。,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

7、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%，相比低碳钢其等级和强度更高。,High carbon steel containing from 0.6 to 2.11 percent carbon,these

8、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，har

9、dness,toughness,or temperature resistance is needed.它们的应用包括机加工中的切削刀具、压铸（法）中的模具、成型法模具（成型模）以及其他，在高碳钢中，必须结合高强度、硬度、刚性或耐热性。,Paragraph 3,Stainless steel require alloy additions to prevent damage from a corrosive atmosphere.不锈钢需要添加合金防止腐蚀环境的破坏。Stainless steels are more resistant to rusting and staining than

10、 carbon and low alloy steels,due primarily to the presence of chromium addition.不锈钢由于加入了铬元素，其抗锈蚀和污斑能力高于碳钢和低合金钢。The amount of chromium is at least 12.7 percent and usually as high as 30 percent,which permits a thin protective surface layer of chromium oxide to form when steel is exposed oxygen.铬的含量至少

11、12.7%，通常达到30%，当钢暴露于氧气环境中时，它允许形成一层薄的铬氧化保护层。,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强化机理来分，不锈钢可以分为四种：

12、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,The austenitic stainless steels have the austenite structure retained at room temperature.奥氏体不锈钢在室温保留奥氏体结构。The austenite has the fcc structure and is stable above 910.奥氏体有面心立方结构，910以上处于稳定状态。This structure can occur at room temperature when it is stabilized b

13、y an appropriate alloy addition such as nickel.通过添加诸如镍等恰当的合金，这一结构能够在室温下形成。,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 corrosion resistance of austenitic stainless steel

14、s,these lower alloy(and less expensive)ferritic stainless steels are quite serviceable.对于许多不需要高腐蚀抵抗能力的奥氏体不锈钢应用来说，这些低合金铁素体不锈钢可用。,A rapid quench heat treatment discussed later allows the formation of a more complex body centered tetragonal crystal called martensite.后面讨论的快速淬火热处理允许以四方晶体为中心的更复杂基体的形成，称为马氏

15、体。tetragonal:四角形的This crystal structure yields high strength and low ductility.这种晶格结构产生高强度、低韧性。,As a result,these martensitic stainless steels are excellent for applications such as cutlery and springs.结果，这些马氏体不锈钢对于诸如刀具和弹簧等应用来说是非常优秀的。Precipitation hardening is another heat treatment.Essentially,it i

16、nvolves producing a multiphase microstructure from a single phase one.沉淀硬化是另外一种热处理。本质上说，它涉及到从一个单一相产生多相微结构。,The result is increased resistance to dislocation motion and,thereby,greater strength or hardness.结果是位错运动阻力增加，因此强度和硬度变得更高。Precipitation hardening stainless steels can be found in applications s

17、uch as corrosion resistant structural members.沉淀硬化不锈钢能够在诸如抗腐蚀结构件应用中发现。,Paragraph 5,Cast iron are iron-carbon alloys that pass through the eutectic reaction during solidification and greater than 2.11 percent carbon.铸铁是铁和碳的合金，碳含量大于2.11%，通过在凝固过程中的共晶反应得到。There are five important types of cast irons.有五种

18、重要类型的铸铁。White cast iron contains massive amounts of cementite and is a hard,brittle,unmachinable alloy.白铸铁包含大量的渗碳体，是硬、脆和不能加工的合金。,Gray cast iron contains small,interconnected graphite flakes that cause low strength and ductility.灰铸铁含有小的、互相连接的片状石墨，造成低强度和低塑性。A significant silicon content(2 to 3 percent

19、)promotes graphite precipitation rather than cementite.有效的硅成分促进石墨沉淀而不是渗碳体。The sharp,pointed graphite flakes contribute to characteristic brittleness in gray iron.锋利的点状的石墨片使灰铸铁很脆。,Malleable cast iron is produced by the heat treatment of white iron,causing cementites decomposed to irregular but rounde

20、d clumps of graphite.可锻铸铁通过白铸铁热处理产生，导致渗碳体分解为不规则的、但为圆形的石墨块。This graphite form permits good strength,ductility and toughness in the iron.这种石墨形式允许良好的强度、塑性和刚度。Ductile or nodular cast iron contains spheroidal graphite particles.易延展的或球墨铸铁包含球状的石墨颗粒。,These spheroidal graphite are obtained during solidificat

21、ion by the addition of small amounts of magnesium to the molten iron.球墨铸铁指通过在结晶过程中添加一些镁元素作为球化剂而得到的。This resulting ductile iron derives its name from the improved mechanical properties compacted graphite cast iron contains vermicular graphites.这种球墨铸铁因为提高力学性能而获得他的名字，密实的石墨铸铁含有蠕虫状石墨,They are also obtain

22、ed during solidification by the addition of magnesium or rare earth elements.它们也通过加入镁或稀土元素凝固而获得。The structure and properties of compacted cast iron are intermediate between gray and ductile irons.蠕墨铸铁的性质和结构介于灰铸铁和球墨铸铁之间。,Lesson 2 Nonferrous metals,Words and Expressions,Paragraph 1,Although ferrous al

23、loys are used in the majority of metallic applications in current engineering designs,but nonferrous alloys play a large and indispensable role in our technology.尽管黑色金属合金用于目前大多数工程设计的金属材料应用，但是有色合金在我们的科技中也起到了非常巨大和必需的角色。The most important nonferrous metals are copper,aluminum,lead,zinc,tin,but all thes

24、e metals are used much less than ferrous metals,because the ferrous metals are much cheaper.最重要的有色金属是铜、铝、铅、锌、锡，但是这些金属的应用远低于黑色金属，因为黑色金属更便宜。,Paragraph 2,Aluminum are best known for low density and corrosion resistance.铝众所周知密度低，耐腐蚀能力强。It has a density of 2.70g/cm3 or one third the density of steel.密度为2

25、.70g/cm3，钢密度的1/3。Although aluminum alloys have relatively low tensile properties compared to steel,their strength-to-weight ratio is excellent.尽管铝合金相对钢来说具有更低的拉伸性质，但是它们具有优良的强度重量比。,Aluminum is often used when weight is an important factor,as in aircraft and automotive applications.当重量是一个重要因素的时候，铝经常被使用

26、，比如飞机和汽车。On the other hand,aluminum often does not play an endurance limit in fatigue,so failure eventually occurs even at rather low stress.另外，铝疲劳极限较低，因此即使在低应力下也会失效。Because of its low melting point,aluminum does not perform well in the high temperatures.因为低熔点，铝不能很好的应用于高温环境下。,Finally,aluminum alloys

27、 have a low hardness,leading to poor wear resistance.最后，铝合金硬度低，耐磨损能力低。Aluminum alloys can be subdivided into two groups,wrought aluminum and casting aluminum alloys.铝合金可以细分为两类：锻造铝合金和铸造铝合金Wrought alloys are shaped by plastic deformation.形变铝合金通过塑性变形而形状改变。They have compositions and microstructures sign

28、ificantly different from casting alloys.它们具有不同于铸造合金的成分和微结构。,It reflects the different requirements of manufacturing process.它反映了制造过程的不同要求。Within wrought alloys group we can divide the alloys into two subgroups-heat treatable and nonheat treatable alloys.在形变合金中，我们能够把合金划分成两子群：可热处理合金和不可热处理合金。Heat treat

29、able alloys have a high hardness,whereas nonheat treatable alloys are hardend by solid solution strengthing.热处理合金具有高硬度，然而不可热处理合金通过固溶时效强化硬化。,如图所示，合金在平衡状态图上有固溶度的变化，并且固溶度随温度降低而减小，如果将C0成分的合金自单相固溶体状态缓慢冷却到固溶度线(MN)以下温度(如T3)保温时，相将从相固溶体中脱溶析出，相的成分将沿固溶度线变化为平衡浓度Cl，这种转变可表示为(C0)(C1)+，反应产物为呈平衡状态的(+)双相组织。将这种双相组织加热到

30、固溶度线以上某一温度(如T1)保温足够时间，将获得均匀的单相固溶体相，然后速冷，抑制相分解，获得在室温下过饱和的相固溶体，这种处理称为固溶处理。由于这种处理与前述的淬火处理相似，故有时也称为淬火，但与淬火有本质的区别。,固溶处理获得的过饱和固溶体在室温或较高温度下等温保持时，溶质原子会在固溶体晶格中的一定区域内聚集或组成第二相，这种现象称为析出。在析出过程中，合金的力学性能、物理性能和化学性能等随之发生变化，这种现象称为时效。室温下产生的时效称为自然时效，高于室温的时效称为人工时效。由于第二相的析出，使合金的强度和硬度升高的现象称为时效强化，是强化合金材料的重要途径之一。能够发生时效现象的合金

31、称为时效合金，成为这种合金的条件是能够形成有限固溶体且其固溶度随温度的降低而减小。固溶时效强化处理主要用于沉淀硬化不锈钢及非铁合金如Al-Cu-Mg系合金、复杂青铜中。高锰钢或高铬高镍钢这类奥氏体钢常用固溶处理来抑止缓冷过程中碳化物的析出以保证钢的耐磨性或耐蚀性，方法是将钢加热到10501100保温后在水中冷却。,Paragraph 3,Copper alloys possess a number of superior properties.铜合金拥有许多优良的性质。Their excellent electrical conductivity makes copper alloys the

32、 leading material for electrical wiring.它们优良的导电能力使得铜合金是电线中的主要材料。Their excellent thermal conductivity leads to applications for radiators and heat exchangers.它们优良的导热性可以用于散热器和热交换器。Superior corrosion resistance is exhibited in marine and other corrosive environments.优良的耐腐蚀能力体现在海运或其他腐蚀环境中。,The fcc struc

33、ture contributes to their generally high ductility and formability.面心立方结构使它具有较高的延展性和成型能力。Copper alloys are also unique in that they may be selected to produce an appropriate decorative color.铜合金也是独一无二的，就在于它们可以被选择来作为装饰性的颜色。Pure copper is red.纯铜是红色的。However zinc additions produce yellow color and nick

34、el produce a silver color.然而加入锌之后产生黄色，加入镍之后产生银色。,The copper can take advantage of all of the strengthening mechanism.铜能够利用所有的强化机理。So there are a myriad of copper-base alloys.因此有无数种铜基合金。The copper-zinc alloys are known as brass.铜锌合金为黄铜Manganese bronze is a particularly high-strength alloy containing

35、manganese as well as zinc for solid solution strengthening.锰青铜尤其是高强度的合金，含有锰和锌用于固溶时效强化,A copper-nickel-zinc ternary alloy is called nickel silver.铜-镍-锌三元合金被称为镍黄铜/洋铜。Although it does have a silver color,but it really has no silver present.尽管它有银色，但是它不含有银。The formability of these alloys approaches that

36、of copper-zinc alloys.这些合金的成型能力接近铜锌合金。,Magnesium alloys have even lower density than aluminum and,as a result,appear in numerous structural applications such as aerospace designs,high speed machinery,and transportation and materials handling equipment.镁合金密度更低，常常用于诸如航天设计、高速机械、运输设备和材料处理设备等无数结构应用。Howev

37、er,magnesium has a low modulus of elasticity and poor resistance to fatigue,wear.然而，镁合金具有比较低的弹性模量，并且抗疲劳和耐磨损性能也比较差。,Magnesium also pose a hazard during casting and machining,since it combines easily with oxygen and burns.镁在铸造和加工过程中存在危害，由于它容易和氧气结合并且燃烧。Finally,the response of magnesium to strengthening

38、 mechanisms is relatively poor.最终，镁对强化机理的响应是相对较差的。In magnesium alloys,strengthening is achieved by solid solution strengthening,strain strengthening;grain size control,dispersion strengthening,and age harding.所以，镁合金是通过固溶强化，加工强化，细晶强化，弥散强化和时效强化来使其强化。,As in aluminum alloys,the solubility of the alloyin

39、g elements in magnesium is rather low,so the degree of solid solution strengthening is limited.正如在铝合金中一样，合金元素在镁中的溶解能力更低，因此固溶时效强化程度有限。,Paragraph 4,Nickle alloys are used for corrosion protection and for high temperature resistance.镍合金被用于腐蚀保护和耐高温环境中。It takes advantages of its high melting points and h

40、igh strengths.它充分利用它的高熔点和高强度。The lattice of nickle is FCC structures and has good formability.镍晶格是面心立方结构，有良好的成型能力。Nickle alloys have much in common with cooper alloys.镍合金在很多方面和铜合金相同。,We have already used the Ni-Cu system as the classic example of complete solid solubility.我们已经使用镍-铜系统作为完全固溶的经典例子。When

41、 copper is added to nickle,the maximum strength is obtained near 60 percent Ni.当铜添加到镍中，最大强度达到镍的60%。A number of alloys,called Monels,contain approximately this composition.许多合金称为蒙乃尔铜-镍合金，大约包含这一成分。They are used in salt water and at a relative high temperature for their strength and corrosion resistanc

42、e.它们被用在盐水中和相对高温环境中，因为它们的强度和耐蚀能力。,Nickles is harder than copper,but monel is harder than nickle.镍比铜硬度更高，但是蒙乃尔比镍硬度更高。Nickle exhibits excellent corrosion resistance and high temperature strength.镍具有良好的耐蚀能力和高温强度。Some of the monels contain small amounts of aluminum and titanium.一些蒙乃尔中包含小量的铝和钛。These alloy

43、s show an age-hardening.这些合金时效强化。Superalloys contain large amounts of alloying elements.超合金包含大量的合金元素,These elements can produce a combination of high strength at elevated temperature,resistance to deformation at temperatures up to 1000,and resistance to corrosion.这些元素能够在升高的温度中具有高强度，温度达到 1000具有较好的抗变形

44、能力和耐蚀性。There are three categories of superalloys.有三种超合金They are nickle base alloy,iron-nickle base alloy,and cobalt base alloy.他们分别是：以镍为基的合金，以铁-镍为基的合金，以钴为基的合金。Typical use includes vanes for turbine and jet engines,heat exchangers,chemical reaction vessel components,and heat-treating equipment.典型的应用包

45、括涡轮和喷气式发动机的叶片、热交换器、化学反应容器和热处理设备。,Paragraph 5,Different metals are produced in different ways,but almost all the metals are found in the form of metal ore(iron ore,copper ore,etc.).不同的金属制造方法也不一样，但是大多金属都是通过各种各样金属矿石提炼出来的（例如：铁矿石，铜矿石等）。The ore is a mineral consisting of a metal combined with some impurit

46、ies.矿石由金属和一些杂质组成。In order to produce a metal from some metal ore,we must separate these impurities from the metal,that is done by metallurgy.为了从金属矿石中提炼金属，我们必须把这些杂质和金属分离，通过冶金术实现。,Lesson 3.Ceramics and Other Materials,Paragraph 1,A ceramic is an inorganic,non-metallic solid prepared by the action of h

47、eat and subsequent cooling.陶瓷是一种无机非金属固体，通过加热行为和随后的冷却练制。Ceramic materials may have a crystalline or partly crystalline structure,or may be amorphous(e.g.,a glass).陶瓷材料可能是晶状的、部分晶状的或无定型的(非晶态的)结构。Because most common ceramics are crystalline,the definition of ceramic is often restricted to inorganic crys

48、talline materials,as opposed to the non-crystalline glasses.因为许多常见的陶瓷是晶体结构，所以陶瓷的定义经常局限于无机晶体材料，和非晶玻璃相反。,Paragraph 2,Ceramics have been traditionally known as hard materials that can withstand harsh environments and high temperature.传统上认为陶瓷是一种很硬的材料，它可以经受住严酷的环境和高温。These attributes have lead to their us

49、e in applications such as cutting tools and turbine coatings.这些属性导致它们应用于切削刀具和涡轮涂层。However,ceramics are also rich in electrical and magnetic properties,which have lead to their use as insulators,dielectrics,superconductors,magnets,electrodes,and electrolytes.然而，陶瓷具有丰富的电、磁性质，这使得它们被用作绝缘子，电介质，超导体，磁铁，电极和

50、电解质。,Paragraph 3,Ceramics are used in the manufacture of knives.陶瓷用于刀具的制造The blade of a ceramic knife will stay sharp for much longer than that of a steel knife,although it is more brittle and can be snapped by dropping it on a hard surface.陶瓷刀片比钢刀保持锋利时间更长，尽管它更脆和落到硬表面时更易折断。Ceramics such as alumina a