南京工业大学机械工程英语考题翻译

1、1. fracture toughness can be described as a material，s ability to avoid fracture, especially when a flaw is in troduced metals can gen erally contain n icks and dents without weakeni ng very much, and are impact resistant a football player counts on this when he trusts that his facemask won' t s

2、hatter.断裂韧性可以描述为材料防止断裂特别是出现缺陷时不断裂的能力。金属一般能在 有缺口和凹痕的情况下不显著削弱，并且能抵抗冲击。橄榄球运动员据此相信他的面罩不会 裂成碎片。2. plastic deformation is the ability of bend or deform before breaking. as engineers, we usually design materials so that they don' t deform under normal conditions you don' t want your car to lean to

3、the east after a strong west wind.塑性变形就是在断裂前弯曲或变形的能力。作为工程师，设计时通常要使材料在正 常条件下不变形。没有人愿意一阵强烈的西风过后白己的汽车向东倾斜。3. forging refines the grain structure and improves physical properties of the metal. with proper desig n, the grain flow can be orie nted in the directi on of prin cipal stresses encoun tered in a

4、ctual use铸造细化金属的晶粒组织、改善其物理性能。通过适当的设计，可以使晶粒流动方 向与实际使用时的主应力方向一致。4. a drill jig is a device for ensuring that a hole to be drilled, tapped, or reamed in a workpiece willbe machined in the proper place.钻模是一种确保在工件正确位置进行钻孔、攻丝或饺孔加工的装置。a fixture holds the work during machining operations but does not contai

5、n special arrangements for guiding the cutting tool ,as drill jigs do.夹具在机加工作业时夹持工件，但它不象钻模那样包含引导切削刀具的特殊布置。5. the unilateral system permits changing the tolerance while still retaining the same allowanee or type of fit. with the bilateral system, this is not possible without also changing the nominal

6、 size dimension of one or both of the two mating parts.单向体系允许在依然保留相同允差或配合类型的情况下改变公差。而双向体系在不同时改变 一个或两个配合零件名义尺寸的情况下，这是不可能做到的。6. dimensions that affect the function of the part should always be specified and not left as thesum or difference of other dimensions.影响零件功能的尺寸总是应该标注的而不要留作其它尺寸的和或差。 if this is

7、not done, the total permissible variation on that dimension will form the sum or difference of the other dimensions and their tolerances, and this will result in these tolerances having to be made unnecessarily tight. the overall dimension should always appear.如果不是这样，那尺寸允许的总的变化将形成其它尺寸及它们的公差 的和或差，这会导

8、致这些公差不得不定得过紧。总尺寸一般应该标注。段落一：cutting fluids 切削液the functions of cutting fluids (which are often erroneously called coolants) are:to cool the tool and workpieceto reduce the friction切削液(经常误称为冷却液)的功能如下：冷却刀具和工件减少摩擦to protect the work against rustingto improve the surface finishto prevent the format!on of

9、 built-up edgeto wash away the chips from the cutting zone保护工件不生锈改善表面光洁度防止切屑瘤的形成从切削区冲掉切屑however; the prime function of a cutting fluid in a metal cutting operation is to control the total heat. this can be done by dissipating the heat generated as well as reducing it. the mechanisms by which a cutti

10、ng fluid performs these functions are: cooling action and lubricating action.然而，在金属切削作业中切削液的主要功能是控制总热量。这可通过既散发乂减少 所产生的热量来达到。切削液实现这些功能的机理是：冷却作用和润滑作用。cooling action. originally it was assumed that cutting fluid improves the cutting performanee by its cooling properties alone. that is why the name cool

11、ant was given to it.冷却作用：最初设想切削液仅仅是通过冷却特性来改善切削作业。这也是它曾被称 为冷却液的原因。since most of the tool wear mechanisms are thermally activated, cooling the chip tool interface helps in retaining the original properties of the tool and hence prolongs its life.由于大多数刀具的磨损机理都是由热引起的，冷却切屑刀具接触界面有助于保持刀具的原有 特性，从而延长其使用寿命。ho

12、wever; a reduction in the temperature of the workpiece may under certain conditions increase the shear flow stress of the workpiece, thereby decreasing tool life. it has been shown through a number of investigations that cooling in fact is one of the major factors in improving the cutting performa n

13、ee.可是工件温度的降低在特定条件下会增加工件的剪切流动应力，从而降低刀具寿命。通过一 些研究已经表明实际上冷却只是改善切削作业的主要因素之一。lubricating action. the best improvement in cutting performanee can be achieved by the lubricating action since this reduces the heat gen erated, thus reduci ng the energy input to the metal cutting operation.润滑作用：切削作业的最大改善可通过润滑

14、作用来达到，由于它减少了热量的产生 因而减少了金属切削作业的能量输入。however; if the cutting fluid is to be effective, it must reach the chip tool in terface. but it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turni ng tool, specially when the chip-tool con tact pressure is

15、 as high as 70 mpa.可是，如果要使切削液起作用就必须让它到达切屑刀具接触界面。但如何在采用单尖刀具连 续车削的场合尤其是切屑刀具接触压力高达70mpa时实现并非易事。mercha nt thought that minute asperities existed at the chip-too i in terface and the fluid was draw n into the in terface by the capillary actio n of the in terlocki ng n etwork of these surface asperities.m

16、erchant认为：在切屑与刀具接触界而上存在微小的粗粒，切削液通过这些表而的微小粗 粒组成连锁的网络的毛细管被吸入到切屑与刀具的接触界面上。段落二：electropolishingelectropolishing is an electrochemical process similar to, but the reverse of, electroplating. the electropolishing process smoothes and streamlines the microscopic surface of a metal object. mirror-like finis

17、hes can be obtained on metal surfaces by electropolishing 电解抛光电解抛光是一种与电镀相似的电化学工艺，但过程与电镀正好相反。电解抛光工艺使 金属物体的微观表面平滑和简单化。通过电解抛光能在金属表面得到镜面光洁度。in electropolishing, the metal is removed ion by ion from the surface of the metal object being polished electrochemistry and the fun damental principles of electro

18、lysis (faraday* s law) replace traditional mechanical finishing techniques在电解抛光中，金属是逐个离子地从被抛光金属物体表面去除的。电化学和电解基 本原理(faraday定理)取代了传统的机械精加工技术。in basic terms, the object to be electropolished is immersed in an electrolyte and subjected to a direct electrical curre nt the object is maintai ned ano die, w

19、ith the cathodic corm ecti on being made to a n earby metal con ductor.用基本术语说，要电解抛光的物体被浸没在电解液中并且通上直流电。该物体为阳极，阴极 连接到附近的金属导体上。smoothness of the metal surface is one of the primary and most advantageous effects of electropolishing. during the process, a film of varying thickness covers the surface of the metal. this film is thickest over micro depressions