河南科技大学材料专业英语译文(2).doc

二、材料
2-1 ferrous alloys铁合金（黑色金属）
More than 90% by weight of the metallic materials used by human beings are ferrous alloy. This represents an immense family of engineering materials with a wide range of microstructures and related properties. The majority of engineering designs that require structural load support or power transmission involve ferrous alloys. As a practical matter, those alloys fall into two broad categories based on the carbon in the alloy composition. Steel generally contains between Wc=0.05% and Wc=2.0%.

人们所使用的在重量方面超过90%的金属材料是铁合金。这表明一个巨大的工程材料家族有许多的微观组织和相关性能。大部分的工程设计,需要结构上的负载支撑或动力传输所用到的铁合金。实际上,这些合金基于碳占合金组成的含量可分为两大类。钢的含碳量一般包含在Wc = 0.05%和Wc =2.0%。铸铁的碳含量一般在Wc =2.0% and Wc =4.5%
Within the steel category, we shall other than carbon is used. A composition of 5% total non-carbon additions will serve as an arbitrary boundary between low alloy and high alloy steels. Those alloy additions are chosen carefully because they invariably bring with them sharply increased material costs. They are justified only by essential improvements in improvements such as higher strength or improved corrosion resistance。在钢的这一类别,我们可以区分除了碳之外是否有其他明显的合金添加元素。组成含有5%的非碳合金元素可以作为低合金钢和高合金钢的仲裁界限。由于加入这些合金元素会急剧提高材料的成本，故要慎重选用。他们可以从本质上提高钢的性能，如钢的高强度或抗腐蚀性能的提高。
2.1.1　钢铁
The earth contains a large number of metals which are useful to man. One of the most important of these is iron. Modern industry needs considerable quantities of this metal, either in the form of iron or in the form of steel. A certain number of non-ferrous metals, including aluminum and zinc, are also important, but even today the majority of our engineering products are of iron or steel. Moreover, iron possesses magnetic properties, which have made the development of electrical power possible. 地球包含大量的对人们有用的金属。其中最重要的就是铁。现代工业需要大量这样的金属,无论是铁的形式或钢的形式存在.一定量的有色金属,包括铝和锌,也很重要,但即使是在今天,但是如今我们的大部分工程产品是钢铁。此外,铁具有磁性的性能,使电力的发展成为可能.
The iron ore which we find on earth is not pure. It contains some impurities that must be removed by smelting. The process of smelting consists of heating the ore in a blast furnace with coke and limestone, and reducing it to metal。 Blasts of not air enter the furnace from the bottom and provide the oxygen that is necessary for the reduction of the ore. The ore becomes molten, and its oxides combine with carbon from the coke. the non-metallic constituents of the ore combine with the limestone to form a liquid slag。 This floats top of the molten iron, and passes out of the furnace through a tap. The metal which remains is pig iron. 我们在地球上发现的铁是不纯净的。它包含一些必须通过被冶炼来去除的杂质。冶炼过程是在有焦炭和石灰石存在的高炉中加热矿石,从而把他提炼成金属。热空气从底部进入熔炉并提供了矿石反应所需要的氧气,这是必要的森林采伐量减少矿石. 矿石变为熔融态，氧原子和来自焦炭中的碳原子结合。矿石中的非金属成分与石灰石 结合形成液态熔渣.熔渣浮在融化态的铁（铁液）的顶端 从熔炉的口部流出。剩下的金属就是生铁.
We can melt this down again in another furnace a cupola with more coke and limestone, and tap it out into a ladle or directly into molds. This is cast iron. Cast iron does not have the strength of steel. It is brittle and may fracture under tension. But it possesses certain properties that make it very useful in the manufacture of machinery. In the molten state it is very fluid, therefore, it is easy to cast it into intricate shapes. Also it is easy to machine it. Cast iron contains small proportions of other substances. These non-metallic constituents of cast iron include carbon, silicon and sulphur, and the presence of these substances affects the behavior of the metal. Iron which contains a negligible quantity of carbon, for example, wrought iron behaves differently form iron which contains a lot of carbon. 我们可以把生铁在另一个熔炉—冲天炉—和更多的焦炭与石灰石再次融化，然后浇入钢水包或直接浇入模具。这就是铸铁。铸铁没有像钢一样的强度。它是脆的,在拉力作用下容易折断。但它所具有的某些性能,使它在机械制造方面非常有用。在熔融状态下它的流动性很好，因此,它能很容易浇注在复杂的形状里。 它也很容易用机器切削。铸铁含有一小部分的其他物质。铸铁中的这些非金属的组分包括碳、硅、硫,这些物质的出现影响着金属的表现。例如，可锻铸铁和含碳量高的铁所表现的性能不同（含有极少量的铁如精炼铁，其特性与含大量碳的铁不同）。
The carbon in cast iron is present partly as free graphite and partly as a chemical combination of iron and carbon which is called cementite. This is a very hard substance, and it makes the iron hard too. However, iron can only hold about 1.5% of cementite. Any carbon content above that percentage is present of the from of a flaky graphite. Steel contains no free graphite, and its carbon content rangers from almost nothing to 1.5%. we make wire and tubing from mild steel with a very low carbon content, and drills and cutting tools from high carbon steel. 在铸铁中的碳部分作为自由的石墨存在，部分以被称为渗碳体的铁和碳的化学混合存在。这是一种非常坚硬的物质,它使铁也变得很坚硬。然而,铁只能持有约1.5%的渗碳体。任何碳含量高于这个百分含量就会以片状石墨存在。钢不含自由（游离）石墨,其碳含量在从零到1.5%变化。我们用含碳量很低的热轧钢来制造电线和管型材料，用高碳钢来制造钻头和切削工具（刃具）
2.1.2Carbon and alloy steel碳钢和合金钢
Carbon steel碳钢
A plain carbon steel is one in which carbon is the only alloying element. The amount of carbon in the steel controls its hardness, strength , and ductility. The higher the carbon content , the harder the steel. Carbon steels are classified according to the percentage of carbon they contain. They are referred to as low, medium, high, and very-high-carbon steels.一般的碳钢，碳是唯一的合金元素。碳在钢中的数量控制着刚的硬度、强度和塑性。碳含量越高,刚就越硬。碳钢根据其中碳的百分含量而被划分。它们被称为低碳钢、中碳钢、高碳钢,和含碳非常高的钢。
Low-carbon steel低碳钢
Steels with a carbon range of 0.05 to .0.30 percent are called low-carbon steels. Steels in this class are tough, ductile, and easily machined, formed, and welded. Most of them do not respond to any heat treating process except case hardening. 碳含量从0.05%到0.30%的钢被称为低碳钢。这类钢韧性好,塑性好,容易加工,形成,和焊接。除了表面渗碳硬化大部分对任何热处理没有回应。
Medium-carbon steels中碳钢
Those steels have a carbon range from 0.30to0.45 percent. They are strong and hard but cannot be worked or welded as easily as low-carbon steels. Because of their higher carbon content, they can be heat treated. Successful welding of these steels often requires special electrodes, but even then greater care must be taken to prevent formation of cracks around the weld area.这类钢的碳含量从0.30%到0.45%。他们强度和硬度很高，但不能像低碳钢一样容易被加工和焊接。因为他们有更高的碳含量,他们可以进行热处理。通常需要采用特殊焊条才能成功地焊接这类钢材，即使这样，也要非常小心，避免在焊接区形成裂纹。
High and very-high-carbon steels高碳钢和含碳非常高的碳钢
Steels with a carbon range of 0.45 to 0.75 percent are classified as high-carbon and those with 0.75 to 1.7 percent carbon as very-high-carbon steels. Both of those steels respond well to heat treatment. As a rule, steels up to 0.65 percent carbon can be welded with special electrodes, although preheating and stress relieving techniques must be used after the welding is completed. Usually it is not practical to weld steels in the very-high-carbon range.
含碳在0.45%至0.75%的钢被归为高碳和那些含碳0.75%到1.7%的钢是含碳量非常高的钢。这两种钢对热处理都有很好的回应。通常来说，碳的质量分数在0.65%以上的钢都可以采用特殊的焊条进行焊接，尽管通常需要采用预热及焊后消除应力处理。通常含碳量非常高的钢不适合进行焊接。
Carbon is the principal element controlling the structure and properties that might be expected from any carbon steel. The influence that carbon has in strengthening and hardening steel is dependent upon the amount of carbon present and upon its microstructure. Slowly cooled carbon steels have a relatively soft iron pearlitic microstructure ;whereas rapidly quenched carbon steels have a strong ,hard, brittle, martensitic microstructure.碳是任何一种碳钢得到期望的组织和性能的主要控制元素。碳对强化硬化的钢的影响取决于碳的百分含量和碳的微观组织。缓慢冷却的碳钢有一个相对软铁珠光体微观组织;然而淬火碳钢有高强度，高硬度，易碎的马氏体微观组织。
In carbon steel, at normal room temperature, the atoms are arranged in body-centered lattice. this is known as alpha iron. And a combination of iron and carbon .The compound of iron (ferrite) and a combination of iron and carbon. The compound of iron and carbon, or iron carbide cementite is very hard and has practically no ductility.
碳钢在室温下,原子以体心立方晶格排列。这就是众所周知的阿尔法铁。这种组织的每个颗粒由纯的铁素体片层和铁和碳化合的片层组成。铁和碳的化合物，或者说碳化铁，叫做渗碳体。这种渗碳体很硬而几乎没有塑性。
In a steel with 0.8 percent carbon, the grains are pearlitic, meaning that all the carbon is combined with iron to form iron and carbide. This is known as a eutectoid mixture of carbon and iron. See figure含碳0.8%的碳钢,晶粒是珠光体的组织,这意味着所有的碳和铁结合形成碳化铁。这被称为碳和铁的共析混合物。见图2.1
If there is less than 0.8 percent carbon, the mixture of pearlite and ferrite is referred to as hypoeutectoid. An examination of such a mixture would show grains of pure iron and grains of pearlite as shown in figure 2.2如果碳含量不足0.8%,珠光体和铁素体的混合物就是亚共析组织。检验这种由纯铁晶粒和珠光体晶粒组成的混合物如图2.2
When the metal contains more than 0.8 percent carbon ,the mixture consists of pearlite and iron carbide and is called hypereutectoid. Notice in figure 2.3 how the grains of pearlite are surrounded by iron carbide. In general ,the greatest percentage of steel used is of the hypoeutectoid type, that which has less than 0.8 percent carbon.当金属含碳量大于0.8%,混合物由珠光体和碳化铁组成被称为过共析组织。如图2.3展示了珠光体是如何被碳化铁所包围的。一般来说, 绝大百分含量所用到钢的是含碳量低于0.8%的亚共析组织类型。

Alloy steel
An alloy steel is a steel to which one or more of such elements as nickel, chromium, manganese, molybdenum, titanium, cobalt, tungsten, or vanadium have been added. The addition of these elements gives steel greater toughness, strength, resistance to wear, and resistance to corrosion. Alloy steels are called by the predominating element which has been added. Most of them can be welded, provided special electrodes are used. 一种合金钢是由一个或多个诸如镍、铬、锰、钼、钛、钴、钨、或钒已添加元素的钢。这些元素的添加使钢有更好的韧性、强度、耐磨性、和耐腐蚀性。合金钢是因被添加的主导元素而命名。大部分合金钢用特殊的焊条可以进行焊接。
　The common elements added to steel and their effects are explained as the following. 最常见的元素添加到钢及其影响如下说明。　
Manganese
The addition of manganese to steel produces a fine grain structure which has greater toughness and ductility. Manganese always presents in a steel to some extent because it is used as a deoxidiser. 在钢中加入锰会生成使金属有很好的韧性和塑性的细晶组织。锰总是一定程度出现在钢中,因为它被用作脱氧剂。　
Silicon
Always present to some extent, because it is used with manganese as a deoxidiser. 总是一定程度的存在,因为它和锰共同作为脱氧剂。
Chromium
When quantities of chromium are added to steel the resulting product is a metal having extreme hardness and resistance to wear without making it brittle. Chromium also tends to refine the grain structure of steel, thereby increasing its toughness. It is used either alone in carbon steel or in combination with other elements such as nickel, vanadium, molybdenum, or tungsten钢中加入大量的铬以后，硬度变得非常高，非常耐磨而又不脆。铬也能改善钢的晶粒组织，从而提高它的韧性。铬既可以单独使用在钢中，也可以和镍、钒、钼、钨等元素联合使用
Nickel
The addition of nickel increases the ductility of steel while allowing it to maintain its strength. When large quantities of nickel are added (25 to 35 present), the steels not only become tough but also develop high resistance to corrosion and shock. 钢中镍的添加可以提高钢的塑性,并能够使它的强度保持不变。当大量的镍被添加到钢中(25%到35%),钢不仅变得韧性好而且同时提高了它的耐腐蚀性
Tungsten
　 Tungsten is used mostly in steels designed for metal cutting tools. Tungsten steels are tough, hard, and very resistant wear. 钨在钢中主要用来设计切削工具。钨钢韧性很好,硬度高,耐磨性也非常好。
Molybdenum
　Molybdenum produces the greatest hardening effect of any element except carbon and at the same time it reduces the enlargement of the grain structure. The result is a strong, tough steel. Although molybdenum is used alone in some alloys, often it is supplemented by other elements, particularly nickel or chromium or both. 钼除了碳与任何元素相比能产生最大的硬化效应,同时会减小晶粒组织的变大。结果产生了强度高、韧性高的钢。虽然钼在某些合金中单独使用,但它常常是辅以其他元素使用,特别是镍或铬或两者都用。
Vanadium
Vanadium is a strong carbide forming element. Addition of this element to steel promotes fine grain structure when the steel is heated above its critical range for heat treatment. It also imparts toughness and strength to the metal. It can cause reheat cracking. 钒是一种强度高的碳化物形成元素。当钢中加入这种元素进行热处理加热到临界点时会促进组织细化。它还使金属有很好的韧性和高的强度。它会导致再热裂解　
Titanium
Titanium is a strong carbide forming element. It is not used on its own, but added as a carbide stabiliser to some austenitic stainless steels钛是一种强度高的碳化物形成元素。它不用单独使用,但添加在一些奥氏体不锈钢中做为碳化物安定剂

2.1.3 Cast Irons
As stated earlier, we define cast irons as the ferrous alloys with greater than 2%(w) carbon. They also generally contain up to 3%(w) silicon for control of carbide formation kinetics. Cast irons have relatively low melting temperatures and liquid phase viscosities, do not form undesirable surface films when poured, and undergo moderate shrinkage during solidification and cooling. The cast irons must balance good formability of complex shapes against inferior mechanical properties compared to wrought alloys. 如前所述,我们把碳含量大于2%(w)的铁合金定义为铸铁。他们也通常含有3%(w)硅来控制碳化物形成的动力学。铸铁有相对低熔点温度和液相粘性,当浇注的时候不会形成不良表面膜,在凝固、冷却时有适当的收缩。和锻造合金相比，铸铁必须平衡复杂性状的成型能力和低劣的力学性能。
A cast iron is formed into a final shape by pouring molten metal into a mold. The shape of the mold is retained by the solidified metal. Inferior mechanical properties result from a less uniform microstructure, including some porosity. Wrought alloys are initially cast but are rolled or forged into final, relatively simple shapes (in fact, “wrought” simply means “worked”). 铸铁是将融化的金属注入一个模型中而最终成型。模型的外形由固化金属保持。低劣的力学性能起因于包括一些多孔的不均一组织。锻造铸铁是最初铸铁经过滚动或锻造而成的形状相对简单的铸铁 (事实上,“锻造”就是“别加工”的意思)。
There are four general types of cast irons. White iron has a characteristic white, crystalline fracture surface. Large amounts of Fe3C are formed during casting, giving a hard, brittle material. Gray iron has a gray fracture surface with a finely faceted structure. A significant silicon content (Wsi=2%~3%) promotes graphite (C) precipitation rather than cementite (Fe3C). The sharp, pointed graphite flakes contribute characteristic brittleness in gray iron. By adding a small amount (w=0.05%) of magnesium to the molten metal of the gray iron composition, spheroidal graphite precipitates rather than flakes are produced. This resulting ductile iron derives its name from the improved mechanical properties. Ductility is increased by a factor of 20, and strength is doubled. A more traditional form of cast iron with reasonable ductility is malleable iron, which is first cast as white iron and then heat treated to produce nodular graphite precipitates. 铸铁一般分为四种类型。白口铸铁具有白色的,似水晶断面层。大量的Fe3C在铸造过程,形成硬度高，易碎的材料。灰口铸铁有精细面组织的灰色断面层。比较明显的硅含量(Wsi = 2% ~ 3%)促进石墨(C)沉淀而不是形成渗碳体(Fe3C)。锋利的、尖锐的薄片状石墨导致灰口铸铁有典型的脆性。 通过将少量的镁(w = 0.05%)添加到灰铁成分的熔融金属中、就形成球状石墨沉淀而不是片状石墨。结果球墨铸铁得名于改善了的力学性能。塑性增加了20倍,强度增加了一倍。具有适当的韧性的更传统形式的铸铁是可锻铸铁。它首先被铸成白口铸铁，然后热处理形成小球状石墨沉淀。
2.2 Non-ferrous Alloys 有色金属
尽管在现代工程设计中，黑色金属被用在大多数金属的应用方面，但有色金属在工艺中有着巨大而不可缺少的作用。和黑色金属相比，有色金属的数目、种类、当然都过长、复杂，我们也只明确地列出重要的有色金属成员以及他们的主要特性。铝合金是众所周知的密度小、耐腐蚀合金。导电性、加工的容易程度，和外观也都是很重要的特性。因为这些特性，世界上的铝产品在近十年的时间内增加了近一倍。
镁合金比铝合金甚至有更低的密度，因此，镁合金出现在许多诸如说航空航天设计，这些结构上面的应用。铝是面心立方结构材料，因此，有许多（12）个滑移系统致使它有很好的塑性。与之相比镁是只有三个滑移系统的密堆六方结构，因此，镁有典型的脆性。
钛合金自从二次世界大战开始就被广泛使用。在二战前，没有切实的方法把钛金属从活性氧化物和氮化物中分离出来。钛一旦形成，就表现出它优越的反应活性。在其表面形成的一层很薄、有韧性的氧化层，使钛合金有了卓越的耐腐蚀性，这种“钝化现象”在随后会详细地讨论。钛合金和铝、镁一样都有比铁低的密度。尽管比铝、镁密度大，但钛合金在适当的表面温度下有明显的保持其强度的优势，使它可以广泛地应用在航空航天设计方面。钛合金同镁合金一样有密排六方晶格结构，导致它有典型的塑性。但是高温下的体心立方结构，通过加入像钒一样的合金添加元素可以使它在室温下稳定存在。
铜合金拥有一些出众的性能。它卓越的导电性使铜合金成为首选的导电线材料。它们卓越的导热能力使它在散热器和热交换器方面得以应用。出众的耐磨性在海运业和其他耐腐蚀性行业中大显身手。它的面心立方晶格结构使它们有普遍好的塑性和加工性能。它们的镀色经常用在建筑方面。铜合金的广泛应用，在历史上有一些混乱的描述性术语的收藏品。这些铜合金组织性能的可变性比得上钢。高纯度的钢是非常软的材料。在热处理后，加入2w铍形成的CuBe沉淀物可以充分地把合金受拉强度提高到1000MPa。
镍合金和铜合金有许多相似之处。我们已选用Cu-Ni合金系作为比较固体溶解度的经典范例。蒙耐合金是Ni-Cu按质量比约为2:1而得到的商业合金。它们是溶液硬化的很好的例子。镍比铜要硬，但是蒙耐合金比镍还硬。镍展现出卓越的耐腐蚀和高热强。锌合金因为他的低熔点与铁坩埚和模具没有腐蚀性反应，因此是理想的合适的压铸件。汽车部件和计算机硬件就是这类组织的应用。在黑色金属上的镀锌涂层是防腐蚀的重要手段。这种方法被叫做镀锌。
铅合金是耐用的万能材料。