机械专业英语(章跃版)课后英汉翻译

第一章：应力与应变

1.That branch of scientific analysis which motions, times and forces is called mechanics and is made up of two parts, statics and dynamics. 研究位移、时间和力运动乘力是科学分析法的一个分歧，被称作力学，力学由两大部分组成，静力学和动力学。

2.For example, if the force operating on a sleeve bearing becomes too high, it will squeeze out the oil film and cause metal-to-metal contact, overheating and rapid failure of the bearing.

例如：如果止推轴承上的作用力过大的话，会挤出油膜，引起金属和金属之间的相互接触，轴承将过热而迅速失效。

3.Our intuitive concept of force includes such ideas as place of application, direction, and magnitude, and these are called the characteristics of a force.

力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。 4.All bodies are either elastic or plastic and will be deformed if acted upon by forces. When the deformation of such bodies is small, they are frequently assumed to be rigid, i.e., incapable of deformation, in order to simplify the analysis.

所有的物体既可以是弹性的也可以是塑性的，如果受到力的作用就产生变形。当变形很小的时候它们被假设成刚体，也就是不产生变形。 5.The rigid-body assumption cannot be used in internal stresses and strains due to the applied forces to be analyzed. Thus we consider the

body to be capable of deforming.

刚体假设不能应用于内应力和内应变的分析，所以在实际力的分析时，要考虑物体的形变。

6.If all the forces acting on a particle are balanced, the particle will either remain at rest or will continue to move in a straight line at a uniform velocity.

如果作用在质点上所有的力是平衡的，质点将会保持静止或做做匀速直线运动。

第二章：材料的强度与塑性

1.A tensile test consists of slowly pulling a sample of material with a tensile load until it breaks. The ends of tensile specimens are usually enlarged to provide extra area for grip-ping and to avoid having the sample break where it is being gripped.

拉伸试验包括慢慢加载拉伸载荷直到断裂。拉伸试件两端加粗为了提供装夹区域和避免试件断裂。

2.The usual manner of conducting the test is to deform the specimen at a constant speed. For example, in the universal testing machines, the motion between the fixed and moving crossheads can be controlled at a constant speed.

通常进行试验的方法就是使试件以恒定速度发生变形。例如，在万能拉伸试验机上，固定端和移动的十字滑块之间的变形是以恒定速度进行的。

3.The load that must be applied to enforce this displacement rate varies as the test proceeds. This load F may be divided by the cross-sectional area A to obtain the stress in the specimen at any time during the test. 随着实验的进行，用来产生位移的载荷是随位移的变化而变化。在实验中，载荷F除以横截面积A可以得到任意时刻点的应力。 4.However actual measurement of ΔL is preferable where this is feasible. Stress and strain based on the initial (undeformed) dimensions, Ai and Li, are called engineering stress and strain.

然而，在可行的位置上ΔL的实际测量是更可取的，基于原始尺寸Ai和Li的应力和应变称为工程应力和工程应变。

5.Ductile and brittle materials behave differently in compression test as well. The compression test is conducted on short cylindrical specimens placed between parallel plates.

塑性和脆性材料在压缩试验中表现的特性是不相同的。压缩试验是把短圆柱形试件放在两平行平板之间进行的。

6.The compression test diagram for these materials retains the qualitative features of the tension test diagram. The ultimate compressive strength of a brittle of a brittle material is determined in the same way as in tension.材料压缩试验图保持了拉伸试验图性能上的特征。脆性材料的最大压缩强度与最大拉伸强度得到的方法相同。

第七章：砂型铸造

1.The first stage in the production of sand casting must be the design and manufacture of a suitable pattern. Casting pattern has to be made larger than the finished casting size to allow for the shrinkage that takes place during solidification and cooling.在型砂铸造生产中，第一阶段是必须设计和制造合适的模型，考虑到铸件在凝固和冷却期间产生的收缩铸件模型的尺寸要比铸件的尺寸大。

2.If a hollow casting is to be made the pattern will include extension pieces so that spaces to accept the sand core are molded into the sand. These additional spaces in the mold are termed core prints.如果铸造空心铸件时模型上包含伸长杆便于在砂中放置砂芯的空间称为型芯座。

3.Sand molds for the production of small and medium-sized castings are made in a molding box. The mold is made in two or more parts in order that the pattern may be removed.中小型尺寸的铸件砂型是在一个砂箱中制造，砂型由两部分或更多部分组成，以利于模型的顺利取出。

4.This process of filling and ramming may be done by hand but mold production is automated in a large foundry with the mold boxes moving along a conveyor, firstly to be filled with sand from hoppers and then to pass under mechanical hammers for ramming.填充和夯实的过程可以手工完成，但在大型铸造中砂型的制

造是自动完成的，砂箱随着传送带移动，首先被料斗中的砂子填满，然后通过机械锤时被打实。

5.The risers should coincide with the highest points of the mold cavity so that the displaced air can readily escape from the mold. The sizes of risers should be such that the metal in them does not freeze too rapidly.冒口应该与型腔的最高点相连接，使得进入的空气可以容易的从模型中溢出，冒口的尺寸应该足够大使模型中金属不会太快凝固。

6.When the metal that has been poured into a sand mold has fully solidified, the mold is broken and the casting is removed. The casting still has the runner and risers attached to it and there will be sand adhering to portions of the surface.当熔的金属被倾倒到砂型内并充分凝固以后，砂型将被打破取出铸件，铸件上依然带有横浇口和冒口并且依然有砂子粘在表面。

第九章 电弧焊

1.arc welding in one form or another is the most widely used form of welding .the electrical supply is low voltage but high amperage and may be either alternating or direct .

电弧焊在一种或另一种形式是应用最广泛的焊接形式。电力供应是低电压，但是大电流，并且可以是交流或直流。

2.the earliest forms of arc welding used carbon electrodes.but nowadays the arc is struck between a metal electrode and work

-piece .the electrode may either be of tungsten or be a consumable metal electrode that melts ,acting as a source of filler metal .

3.电弧焊接的最早的形式使用碳电极，但现在的电弧触发一个金属电极与工件之间，电极可以是钨或可熔化，作为填充金属供源的消耗性金属电极。

an alternating-current arc is broken and re-established at each half cycle and this leads to arc instability although the use of arc-established agents in the flux coating of electrode wires can overcome this problem .

交流电弧被打破并且重新建立在每个半周期，这导致电弧不稳定虽然在电极布线焊剂涂层使用电弧建立剂可以克服这个问题。

4.uncoated welding rods can be used for arc wilding .but it is more usual to use flux-coated electrodes .when steels are welded using uncoated electrodes,oxides and nitrides can form and remain in the weld with a consequent loss of toughness . 未涂覆的焊条可以用于电弧野生植物。但更通常使用的焊剂涂覆的电极。当钢在使用未涂覆的电极焊接，氧化物和氮化物能够形成并保持在焊缝韧性因此而丧失。

5.flux-coated electrodes are widely used .the composition of the coatings is complex and a variety of different coatings are used to cater for different types of welding application .

焊剂涂覆的电极被广泛使用。涂层的组成是复杂和各种不同的涂料是用于配合不同类型的焊接应用。

6.in this case the electron flow is from electrode to work-piece .A concentrated arc issues from the electrode tip and heating of the work-piece is largely confined to the very small ares beneath the electrode .

在这种情况下电子流动是从电极到工件，从电极头和工件的加热浓缩的弧的问题在很大程度上仅限于电极下方的非常小顷。

第十章：钢

1.In simple terms, a plain carbon steel may be said to be an alloy of iron and carbon containing less than 1.7% carbon. In practice, however, these steels rarely contain more than 1.4% carbon and other elements are also present, either as deliberate additions (e. g. manganese) or as impurities (e. g. sulphur and phosphorus).

简单来说，普通碳素钢也被称为含碳量少于1.7%的合金钢。然而事实上，这些钢材中很少有含碳量多于1.4%，同时也含有其它元素，例如一些额外添加物（如锰）或者杂志（如硫和磷）。

2.In the manufacture of this material, complete deoxidation is not carried out and it is made as rimming steel. It is produced as hot and cold worded sheet, strip, rod, wire and tube, and is available in the hot-worked or process annealed condition.

在材料的生产加工中，不能实现脱氧还原反应的钢被称为沸腾钢。它被用来生产热处理或冷处理的薄片、带、棒、电线、和管，并且它适用热轧和退火的情况下。

3.The strength and hardness of these steel is low, but a hard surface can be obtained by carbursing in order to combine a wear-resistant surface with tough core properties.

钢的强度和硬度低，可以通过渗碳的方法获得表面硬化以达到表面耐寒内部韧性较好的特性。

4.As the carbon content is raised above 0.2%, the strength increases into the range required for constructional purposes, but the ductility decreases. The fabrication qualities (working and welding characteristics) of this material are very good.

一旦钢中含碳量上升超过0.2%，结构上的强度会发生巨大变化，但是其延展性会下降。材料的制造质量（承载和焊接特性）非常好。 5.Medium carbon steels are often quenched-hardened and fully tempered to give good strength with maximum toughness, which are the properties required of components such as shafts, gears and connecting rods.

中碳钢常被淬火硬化和高温回火处理以便给予良好的温度和最大的韧性，这些是轴、齿轮和连杆所要求的能力特性。

6.High carbon steels are quench hardened and lightly tempered

to give high hardness with only limited toughness. Material in this classification is mainly used for making fairly small, relatively inexpensive cutting tools so that the group as a whole is known as carbon tool steel.

高碳钢常被淬火硬化和低温回火处理以便给予高硬度和一定韧性。此类材料主要被用于生产相当小、可靠地、廉价的切削工具，者这就是碳素工具钢。

第十一章：金属热加工

1.The principal kinds of heat-treatment used in practice .which differently affect the structure and properties ,and which are assigned to meet the requirements made to the semifabricated materials (castings forgings ,rolled stock ,etc.)and finished articles :are (1)annealing ;(2)normalizing ;(3)hardening and (4)tempering .

所用的主要种类热处理的做法，以不同方式影响结构和性能，并分配给满足于半加工材料制成的要求（铸件锻件，轧材等）和必要的类型：是（1）退火（2）正火，（3）淬火和（4）回火。

2.Normalizing raises the strength and hardness of medium and high-carbon steels by 10 to 15 percent as compared to annealed steel.

正火引起较退火的钢的强度和中等和高碳钢硬度由10至15％。 3.Martensite is very hard and brittle ,having a much higher

tensile strength than the steel with a pearlite microstructure .

马氏体是非常硬且脆的，具有高得多的抗张强度比钢具有珠光体组织。

4.Tempering,or drawing ,is a process of reheating a steel part that has been previously hardened to transform hard martensite into softer structure .the higher the tempering temperature used ,the softer and tougher the piece becomes .

回火，或图中，是再加热先前已硬化改造硬马氏体成较软的结构的钢部件的工艺。回火温度中使用的较高，较软及更严格的片而成。 5.For low carbon steels ,normalizing enables a better surface finish to be obtained in machining and raise the production capacity .

对于低碳钢，正火使得能够在加工得到更好的表面光洁度，并提高生产能力。

6.In commercial tempering the temperature range of 250-425℃ is usually avoided because of an unexplained embrittlement ,or loss of ductility ,that often occurs with steels tempered in this range .

在商业回火250-425℃的温度范围通常是可以避免的，因为一种原因不明的脆化，或延展性的损失，经常发生回火钢在此范围内。

第二十章：数控技术

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