机械类专业英语文章翻译.docx

1、机械类专业英语文章翻译1.Chapter 2(P31) Unit2 Cast Irons In order to understand the fabricating characteristics of cast irons, it is necessary to become familiar with the characteristics of the metal and the various types and classifications that are available.为了了解铸铁的制造特性,它是要熟悉的金属的特性和各种可用的类型和分类 One of the disti

2、nguishing features of all irons is that they have a relatively high carbon content. Steels range up to about 2% carbon. Cast irons overlap with the steels somewhat and range from about 1.5% up to 5% carbon. It is principally the form of the carbon, with is governed by thermal conditions and alloying

3、 elements, that provides various structures that may be classified into the following main type:gray cast iron; white cast iron; ductile(nodular) graphite irons;compacted(vermicular) graphite iron.所有熨斗的一个显着特点是,它们具有相对高的碳含量。钢可达至约2%的碳。铸铁重叠有所钢和范围从约1.5%至5%的碳。是主要的形式的碳,是由热条件和合金元素,提供了各种结构的主要类型如下:灰铸铁,白口铸铁,球墨

4、铸铁(结节)石墨铸铁;压实可分为(蠕)石墨铸铁。 Gray cast iron. The terms gray and white cast iron refer to the appearance of the fractured area. The gray cast iron has a grayish appearance because of the large amount of flake graphite on the surface. The dark sections show the graphite flake. The pearlite type may be mad

5、e fine by faster cooling, or coarse by slow cooling. The size of the section will also determine the structure of the metal; the thinner the section the faster it cools. Thus a casting having large variayions in section will also have large variations in hardness and strength unless special precauti

6、ons are take to ensure uniform cooling. 灰铸铁。的条款灰色和白色的铸铁是指裂缝区域的外观。灰口铸铁的,因为大量的鳞片状石墨的表面上有一个浅灰色的外观。暗部显示的鳞片石墨。珠光体类型可能被罚款降温快,缓慢冷却或粗。的部分的大小也将决定结构的金属部分较薄的冷却速度就越快。因此,具有大的变化部分的铸造硬度和强度也将有大的变化,除非采取特殊的预防措施,以确保均匀的冷却。 The basic composition of gray cast irons is often described in terms of carbon equivalent(CE). Th

7、is factor gives the relationship of the percentage of carbon and silicon in the iron to capacity to produce graphite.灰口铸铁的基本组成中的碳当量(CE)通常被描述。此因子给出能力生产石墨碳和硅中的铁的百分比的关系。 CE=c1+1/3(% si+% p) Where: ct=total percentage carbon The CE value may then be related to the tensile strength of the metal. Irons wi

8、th a carbon equivalent of over 4.3% are called hypereutectic and are particularly good for thermal-shock resistance, such as for ingot molds. The higher strength gray irons. With CE less than 4.3%, are termed hypoeutectic.其中:克拉=百分比碳的CE值然后可将有关的金属的拉伸强度。铁杆具有4.3%以上的碳当量被称为过共晶和特别良好的抗热震性,如锭模。高强度灰铸铁。随着CE小于4

9、.3%,被称为亚共晶。 The compressive strength of gray cast iron is to one its outstanding features. In general, it ranges from 3 to 5 times the tensile strength. As an example, a class-20 gray cast iron which has a tensile strength of 20,000 psi has a compressive strength of 83,000 psi. 灰铸铁的抗压强度是一个突出的特点。在一般情

10、况下,它的范围从3至5倍的拉伸强度。作为一个例子,它具有的拉伸强度为20,000 psi的一类20灰铸铁的压缩强度为83,000 psi。 Gray cast iron is the most widely used of all cast metals. Typical applications are engine blocks, pipes and fittings, agricultural implements, bathtubs, household appliances, electric motor housings, machine tools, etc. 灰口铸铁是最广泛使

11、用的所有铸造金属。典型的应用是发动机缸体,管材和管件,农具,浴缸,家用电器,电机外壳,机床等。 2.Chapter 2 (p46) Unit5 Heat Treatment of Tool Steel The purpose of heat treatment is to control the properties of a metal or alloy through the alteration of the structure of the metal or alloy by heating it to definite (一定的、确定的)temperatures and coolin

12、g at various rates. (热处理是通过加热确定金属或者合金的温度和不同速度冷却来改变它们的结构,以达到控制其性能的目的。)This combination(组合)of heating and controlled cooling determines not only the nature and distribution(分布)of the microconstituents(微组织), which in turn determine the properties, but also the gram(晶粒) size.(这种加热和冷却控制相结合的方法不仅决定了微观组织的性质

13、和分布,进而决定了材料的性能,而且也决定了晶粒尺寸。) Heat treating should improve the alloy or metal for the service intended. (热处理根据需要改变金属或者合金的性质。) Some of the various purposes of heat treating are as follows:(热处理有以下不同的用途:) 1.To remove strains 应变after cold working.(通过冷加工去除应变) 2.2. To remove internal stresses such as those

14、produced by drawing, bending, or welding.(通过拉深、弯曲或者焊接等方法去除内应力) 3. To increase the hardness of the material.(提高材料的硬度) 4. To improve machinability.(提高材料的切削性能) 5. To improve the cutting capabilities of tools.(提高刀具的切削能力) 6. To increase wear-resisting properties (提高耐磨性) 7. To soften the material, as in a

15、nnealing.(用退火使材料变软) 8. To improve or change properties of a material such as corrosion resistance, heat resistance, magnetic properties, or others as required.(改善材料的性能,例如耐腐蚀性、抗热性、电磁性或者所需的其他性能。) Treatment of Ferrous Materials. Iron is the major constituent in the steels used in tooling, to which carb

16、on is added in order that the steel may harden.(铁是工具钢中最重要的元素,在其中加入碳元素以提高钢的硬度。)Alloys are put into steel to enable it to develop properties not possessed by plain carbon steel, such as the ability to harden in oil or air, increased wear resistance, higher toughness, and greater safety in hardening.(在

17、钢中加入合金是为了是其具有普通碳素钢所不具备的特性,如:在空气或水中淬硬的性能;提高耐磨性;更高的韧性;以及在淬火过程中的高可靠性。) Heat treatment of ferrous materials involves several important operations which are customarily referred to under various headings, such as normalizing, spheroidizing, stress relieving, annealing, hardening, tempering, and case hard

18、ening.(钢的热处理包括很多重要的操作,它们通常被冠以不同的名字如:正火、球化处理、去应力、退火、淬火、回火和表面淬火。) Normalizing.It involves heating the material to a temperature of about 100200F (55100 C ) above the critical range and cooling in still air. (正火是将材料加热到临界温度以上华氏温度100200度(摄氏50100度),然后在空气中冷却。) This is about 100F (55C ) over the regular har

19、dening temperature.(这个温度通常低于淬火温度100华氏度(55摄氏度)。) The purpose of normalizing is usually to refine(精炼) grain structures that have been coarsened(粗糙) in forging. (正火的目的是为了改善在锻造以后变得粗大的晶粒。)With most of the medium-carbon forging steels, alloyed and unalloyed, normalizing is highly recommended after forging

20、 and before machining to produce more homogeneous均匀structures, and in most cases, improved machinability.(对于大多数中炭锻钢,不管是否是合金钢,正火通常用来作为锻造和机加工之间的工序以使其产生均匀的组织,在大多数情况下是为了改善钢的可加工性能。)High-alloy air-hardened steels are never normalized, since to do so would cause them to harden and defeat the primary purpos

21、e.(空冷高合金钢不需要正火,因为这样做会使其淬硬而达不到正火的真正目的。) Spheroidizing.球化处理(少一段) Stress Relieving. This is a method of relieving the internal stresses set up in steel during forming, cold working, and cooling after welding or machining.(去应力处理。这是一种消除在锻造、冷加工、焊接及加工后的冷却过程中产生的内应力的方法)It is the simplest heat treatment and i

22、s accomplished完成merely by heating to 12001350F (649732 C) followed by air or furnace cooling.(它是一种最简单的热处理,只需将材料加热到649732C,然后空冷或随炉冷却即可。) Large dies are usually roughed out, then stress-relieved and finish-machined. (大型的锻件通常只是粗略的锻打,经过去应力处理后进行精加工。)This will minimize change of shape not only during mach

23、ining but during subsequent heat treating as well.(这样做不但有利于减少在机加工过程中的变形,而且减少在在后续热处理过程中的变形。)Welded sections will also have locked-in stresses owing to a combination of differential heating and cooling cycles as well as to changes in cross section. Such stresses will cause considerable movement in mac

24、hining operations.(焊接部件由于各部分之间的冷热传递也会产生内应力,在机加工的过程中这些内应力会产生相当大的变形。) Annealing. The process of annealing consists of heating the steel to an elevated temperature for a definite period of time and, usually, cooling it slowly.(退火。退火是将材料加热至高温一段时间,然后将其缓慢冷却。)Annealing is done to produce homogenization and

25、 to establish normal equilibrium conditions, with corresponding characteristic properties.(退火是为了建立具有特殊性能的均匀组织和均衡的内部环境。) Tool steel is generally purchased in the annealed condition.(工具钢通常需要采用退火处理。)Sometimes it is necessary to rework a tool that has been hardened, and the tool must then be annealed. (

26、有的已经变硬的工具需要再加工时,这个工具必须要进行退火处理。)For this type of anneal, the steel is heated slightly above its critical range and then cooled very slowly.(在这种情况下钢需要加热到略高于临界温度,然后非常缓慢冷却。) Hardening. This is the process of heating to a temperature above the critical range, and cooling rapidly enough through the critic

27、al range to appreciably harden the steel.(淬火。淬火是将材料加热到临界温度以上然后使其快速冷却,冷却的速度应足以使钢淬硬。) Tempering.This is the process of heating quenched and hardened steels and alloys to some temperature below the lower critical temperature to reduce internal stresses setup in hardening.(回火。回火是将加热淬硬的钢加热到低于低临界温度以消除在淬火过

28、程中产生的内应力。) Case Hardening. The addition of carbon to the surface of steel parts and the subsequent hardening operations are important phases in heat treating. (表面硬化。在钢制件的表面加入碳然后再进行热处理是热处理的一种很重要的形式。)The process may involve the use of molten sodium cyanide氰化钠mixtures, pack carburizing with activated s

29、olid material such as charcoal or coke, gas or oil carburizing, and dry cyaniding.(在渗碳的方法包括:使用熔融的氰化钠混合物渗碳;使用象木炭或焦炭之类的有活性炭的材料进行固体渗碳;用气体或油渗碳;干法渗碳。) 3.Chapter 3(P52) Unit1Foundry Processes (从第三段)In casting a solid is melted, heated to a proper temperature, and treated to produce a desired chemical comp

30、osition. The molten material, generally metal, is then poured into a cavity or mold which contains it In proper shape during solidification. Thus, in a single step, simple or complex shapes can be made from any metal that can be melted, with the resulting produce having virtually any configuration t

31、he designer for best resistance to working stresses, minimal directional properties, and usually, a pleasing appearance. 在铸造一个坚实的融化,加热到适当温度,和治疗产生想要的化学成分。熔融材料,一般金属,然后倒进一个洞或模具其中包含在凝固过程中合适的形状。因此,在单个步骤中,简单或复杂的形状可以由任何金属可以融化,由此造成的生产在几乎任何配置设计师最佳抗工作应力、最小的定向属性,通常,外观美观。(p56) Founding is one of the oldest indu

32、stries in the metalworking field and dates back to approximately 400B.C. since this early age, many methods have been employed to cast various materials. In this chapter, sand casting and its ramifications receive first attention because they are most used; over 90% of all casting are sand casting.

33、Sand casting is best suited for iron and steel at their high melting temperatures but also predominates for aluminum, brass, bronze and magnesium. Other process of commercial importance are treated, in most cases those for nonferrous metals using permanent molds. 在金属加工领域中,铸造只是最古老的行业之一,远在大约公元前4000年就有了铸造。因为这早