完整版机械类专业英语课文参考翻译Word下载.docx

1、bEn and other elements, finds greater use than anyother metal. Metals consisting of iron combined with some other elements are known as ferrous5ferEs metals;all the other metals are called nonferrous5nCn5ferEs metals. The most important nonferrous metal arecopper5kCpE, aluminumE5lju:minEm, leadli:d,

2、 zincziNk, tintin, but all these metals are used muchless than ferrous metals, because the ferrous metals are much cheaper.在地球上发现的所有元素中，大约三分之二是金属元素，但是并不是所有的金属都能够用于工业上。那些金属我们用于工业上的金属被称为工程金属，最重要的工程金属那就是铁，铁跟碳和其他元素结合形成合金的那些金属比其他金属发现有更大用途。铁与别的其他某些元素相结合而组成的金属称为黑色金属，此外所有其他金属都称为有色金属，最重要的有色金属是-铜，铝、铅、锌、锡。但是使用

3、这些有色金属比使用黑色金属要少的多，因为黑色金属便宜得多。Engineering metals are used in industry in the form of alloys because the properties5prCpEti of alloysare much better than the properties of purepjuE metals. Only aluminum may be largely used in the form ofsimple metal. Metals have such a great importance because of thei

4、r useful properties or their strength, hardness,and their plasticityplAs5tisiti.因为合金的特性比纯金属的好，所以工程金属以合金的形式用于工业，只有铝以纯金属的形式被广泛应用。金属因为具有强度、硬度和可塑性而发挥着特别重要的作用。Different metals are produced in different ways, but almost all the metal are found in the forms of metaloreC:（r） （iron ore, copper ore, etcet cet

5、ra.）以不同的方法生产不同的合金但是几乎所有的金属都是以金属矿的形式（铁矿、铜矿）被发现的。The ore is a mineral5minErEl consistence of a metal combined with some impuritiesim5pjuEriti. Inorder to produce a metal from some metal ore, we must separate these impurities from the metal that is doneby metallurgyme5tAlEdVi.矿石是一种由金属与某些杂质相混合而组成的矿物质，为了

6、用金属矿石来生产出一种金属，我们必须把杂质从金属矿中分离出去，那就要靠冶炼来实现。2. Plastics and Other MaterialsPlastics5plAstik, plB:stik have specific properties which may make them preferable5prefErEbl totraditional materialsmE5tIErIEl for certain uses. In comparisonkEm5pArisn with metals, for example,plastics have both advantages and

7、disadvantages. Metals tend to be corrodedkE5rEud byinorganic7inC:5Anik acids5AsId, such as sulphuricsQl5fjuErik acid and hydrochloric7haidrEu5klC:rikacid. Plastics tend to be resistant to these acids, but can have dissolved or deformed by solvent5sClvEnt, suchas carbon tetrachloride7tetrE5klC:raid,

8、which have the same carbon base as the plastics. Color must beapplied to the surface of metals, whereas it can be mixed in with plastics. Metals are more rigid5ridVid thanmost plastics while plastics are very light, with a specificspi5sifik gravity normally between 0.9 and 1.8.Most plastics do not r

9、eadily5redili conduct5kCndQkt heat or electricityIlek5trIsItI. Plastics soften slowlyand can easily be shapedFeip when they are soft.塑料具有特殊的性能。对于某种用途而言，这些性能使得塑料比传统材料更为可取。例如，跟金属相比较，塑料既有优点也有缺点。金属易受到无机酸的腐蚀，如硫酸和盐酸，塑料能抵抗这些酸的腐蚀，但可被溶剂所洛解或引起变形，例如溶剂四氯化碳与塑料具有同样的碳基。颜色必定只能涂到金属的表面。而它可以跟塑料混合为一体。金属比大多数塑料刚性要好，而塑料则非

10、常之轻，通常塑料密度在0. 9-1. 8 之间。大多数塑料不易传热导电。塑料能缓慢软化，而当其还是在软的状态时，能容易成形。It is their plasticityplAs5tisiti at certain temperatures5temprItFE（r） which gives plastics their mainadvantages over many other materials. It permits the large-scale production of moldedmEuld articles, suchas containers, at an economic u

11、nit cost, where other materials require laboriouslE5bC:riEs and often costlyprocesses involving cutting, shaping, machining, assemblyE5sembli and decoration.在某一温度下塑料是处于塑性状态的，这就使塑料具备超过许多其他材料的主要优点。它容许大量生产单位成本低廉的模制式器件，例如，各种容器。于此，若用其他材料则需要大量劳力和往往需要很费钱的加工工艺，比如，切割、成形、加工、装配和装饰。Plastics not only replace oth

12、er materials. Their properties can be exploitediks5plCit for entirelyIn5taIElInew applications. For example, plastics heart valvesvAlv and other human spare parts have make possiblemany recent developments in surgery5sE:dVEri.塑料不仅可以代替其他材料，而且它的特性能被开拓应用于全新领域，比如：随着最近外科手术的发展可能做成塑料的心脏瓣膜和其他人类的器官。There is

13、no single plastics material which is suitable for all applications. It is important that the mostsuitable plastics should be chosen, and if necessary adaptedE5dApt, for each particular requirement. It is alsoimportant that the properties of the plastics chosen should be exploited to the best advanta

14、ge.没有一种纯塑料材料适用于各个领域，如果有必要改进，对于每个有特殊要求的来说选择最合适的塑料是最重要的，被选择的塑料材料的特性被开拓得到更好的应用也是很重要的。A plastics article may need to differ in design and appearance from a similar article made from anothermaterial such as metal or wood. This is due not only to the properties of plastics but also to thetechniquestek5ni:

15、k employed in fabricating5fAbrikeit plastics. These techniques includeinjectionin5dVekFEn molding5mEuldiN, blow molding, compression molding, extrusioneks5tru:VEn andvacuum5vAkjuEm forming.塑料器件可能需要用其他材料比如：与金属或木材制作的类似的器件从设计和外观上加以区别，这不仅是由于塑料性能不同的原因，也是由于制造塑料产品所用的技术不同所致，这些技术包括：注塑、模制、吹塑模制、压模、挤压和真空成型等。3.

16、Casting and Die-Casting AlloysCasting5kB:stiN is one of the oldest metal working techniques known to man. Our country made metalcastings as early as 2000 B.C., and the process used then is not much different in principle5prinsEpl from theone used today.铸造是入类所掌握的最古老的金属加工技术之一。我国早在公元前 2000 年就已把金属制成铸件，而

17、所使用的工艺从原理上和今天的工艺没有多大的区别。Foundry5faundri processes consist of making molds, preparing and meltingmelt the metal,pouringpC:, pCE the metal into the molds, and cleaning the castings. The product of the foundry is a casting,which may vary from a fraction5frAkFEn of a kilogram to several hundred tons. It

18、 may also vary incompositionkCmpE5ziFEn as practically all metals and alloys can be cast.铸造工艺由制模、备料和金属熔炼，金属液浇注入模和铸件清砂等。铸造的产品是铸件，铸件可能从零点几公斤到几百吨范围变化。实际上所有金属在成分上也是变化的，而合金也可以铸造。The metals most frequently cast are iron, steel, aluminum and so on. Of these, iron, because of its lowmelting point, low price

19、 and ease of control, is outstanding for its suitability9sjU:tEbIlEtI for casting and isused far more than all the others.最常铸造的金属是铸铁、钢、铝等等。这些金属中，铸铁，由于其低熔点，低价格和易控制，因而其铸造适应性是最突出的，而且使用也远比所有其他金属多。Casting is a widely used method of producing metal products, particularly those which areintricate5intrikit.

20、 Since molten materials will readily take the shape of the container into which they arepoured, it is nearly as easy to cast fairly complex shapes as to produce simple forms.由于熔融的物料能容易取得被浇注进去的容器（模型）的形状，因此，几乎像生产简单形状铸件那样颇为容易地铸造出复杂形状的铸件。The place where the metals are cast is called a foundry. The most

21、important of cast metals is cast ironwhich is made from pig iron by remelting it in a special melting furnace5fE:nis called a cupola5kju:pElE.铸造金属的地方叫做铸造车间。最重要的铸造金属是铸铁，铸铁是用生铁在一个特殊的熔炉叫冲天炉的炉子中重新熔炼而制造出来的。From the cupola, the cast iron flows into ladles5leidl of different size, and from these ladles it

22、is pouredinto the molds.从冲天炉中出来的铁水流入到不同规格的铁水包中，并从这些铁水包中被浇注到模型中。The molds may be of two kinds: sand molds and metal molds. A metal mold consists of two hollow partswhich should be joined for pouring the metal into it. The inside of this mold is covered with carbon orgraphite5rAfait so that the metal

23、could not stickstik to the wall of the form. When the metal hassolidifiedsE5lidifai, these hollow parts are disjoined and the casting is taken out. There are also special moldsin which large blocks of steel can be cast. These molds are usually made of cast iron and are calledingot5iNEt molds, which

24、the blocks of steel produced by pouring the metal into these molds are calledingots and the process is called ingot casting.模型有两种类型:砂模和金属模。金属模是由两个中空的部件组成，它们应被联结在一起以便将金属液浇入模箱中。这模腔的内侧是要涂以碳粉或石墨，因此金属不玫于粘贴到型腔壁上口当金属液凝固后，这中空的型箱部件被打开并取出铸件。也有一种特殊模型，在该模型中可以铸造大型钢块。这些模型通常用铸铁米制造，并被称为锭模。而浇注金属液到这些模子中生产出的钢块被称为钢锭。该工

25、艺过程叫锭铸。A relatively5relEtIvlI wide range of nonferrous alloys can be die-cast. The principal base metals used, inorder to commercial importance, are zinc, aluminum, copper, magnesiummA5ni:zjEm, lead, and tin. Thealloys may be further classified as low-temperature alloys and high-temperature alloys;

26、those having a castingtemperature below 538C, such as zinc, tin, and lead, are in the low-temperature class. The low-temperaturealloys have the advantages of lower cost of production and lower die-maintenance5meintinEns costs. As thecasting temperature increases, alloy and other special steels in th

27、e best treated condition are required to resistthe erosioni5rEuVEn and heat checking5tFekiN of die surface. The destructivedis5trQktiv effect of hightemperatures on the dies has been the principal factor in retardingri5tB:d the development ofhigh-temperature die castings.相当大量的有色金属合金可以进行模铸h 用的主要而基本的金

28、属，按其在工业上应用的重要性的顺序是锌、铝、铜、锰、铅和锡。这些合金可以进一步进行分类为低温类合金和高温类合金。铸造温度低于 538的那些合金，就像锌、锡和铅,是属于低温类合金。低温类合金具有低生产成本和低的模具维修费用等优点。当铸造温度上升时，需要最佳条件下处理过的合金钢和其他特种钢来抵抗腐蚀及防止模具表面的热裂纹。高温在模具上的损坏作用已经成为阻碍、延缓高温模铸发展的主要因素。Another factor governing5QvEniN the choice of alloy is the erosivei5rEusiv or solvent5sClvEntaction of the molten metal on the respectiveris5pektiv machine parts and dies. This action increases withtemperature, although it is more pronouncedpr5naunst with some alloys than with others. Aluminum, inparticular, has a destructive action on ferrous metals and, for this reason, is seldom melted in