机械专业英语(章跃版)课后英汉翻译(2)

-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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