冶金专业英语5.6.12

New developments in iron making 炼铁的新发展

During the past century, many efforts were made to develop processes for producing iron for steelmaking that could serve as alternatives to the conventional blast furnace.在过去的一个多世纪里，为了找到能够取代传统高炉的炼铁技术人类做了许多努力。This chapter presents a review of the alternativels processes that have achidved some measure of commercial success.本章将介绍成功商用于工业化炼铁体中的一些新工艺和新技术。

1.Direct reduction technology 1. 直接还原技术

In the history of iron and steelmaking technology, the first process is the direct reduction process. 在钢铁冶炼技术的历史上，最早使用的就是直接还原法。The blast furnace takes the place of the direct reduction process, which is the greteat imtronvement in the metallurgical technology. 高炉取代了直接还原法炼铁是冶金技术的重大进步。With the development of iron and steel industry, coke, on which blast furnace have depended for over 200 years, is becoming more expensive every expensive every year, and supplies of suitable coking coals are becoming scarcer. 随着钢铁工业的发展，200多年以来高炉一直使用的焦炭，价格每年都在增加，合适的焦煤越来越少。The direct reduction process was brought back at the end of the eighteenth century. 在18 世纪末，直接还原法又得以恢复。

Today, technology that produce iron by reduction of iron ore below the melting point of the iron producde is generally classified as direct reduction processes and the products referred to as direct reduced iron(DRI). 现在那些在低于铁的熔点温度以下用还原铁矿石的方法来冶金的技术通常称为直接还原法，其产品称为直接还原铁（DRI）。

According to the reducing agents used, direct reduction technology is commonly classed into two types: gas reduction processes and reduction processes with solid reducing agents. 根据还原剂的使用种类，直接还原法一般可分为气体还原法与固体还原法两类。According to the types of reduction reactors used, it is also classified into four main processes----fluidized bed, shaft furnace, retort, rotary kilin processes. 按使用的还原反应器类型，直接还原法主要分为流化床、竖炉、反应罐和回转窑法四大类。

(1)gas reduction processes （1）气体还原法

Reducing gases are carbon monoxide hydrogen or mixtures of two in gas reduction process. 在气体还原法中，还原剂是一氧化碳，氢气或这两种气体的混合物。They are normally obtained from natural gas. 它们通常从天然气中获得。The carbon monoxide and hydrogen are generated in the methane steam of natural gas reforming processes according to the reaction: CH4+H2O=CO+3H2天然气中甲烷转化为一氧化碳和氢气的反应如下: CH4+H2O=CO+3H2

The shaft-furnace process plays an important part in gas reduction processes. 竖炉法在气体还原法中起着重要的作用。More than 50% of all reduction processes are carried out in a shaft-furnace. For example, the Midrex process is a typical(Fig.5-1). 50％以上的还原过程是在竖炉中进行的，例如米德列法就是一个代表(图5-1)。

Midrex furnace has developed into a main production from of direct reduction processes, since the first steel plant was built and went into production in 1969. 米德列竖炉自1969年最早建成并投产以来，已发展成为直接还原去的主要形式。The largest Midrex furnace has an annual capacity of 800,000 ton. 最大的米德列紧炉年生产能力达到了80 万吨。

The main components of the process are the shaft furnace, the gas reformer, and

系统。Reducing gas enters the reducing furnace through a bustle pipe at the bottom of the reduction zone and flows countercurrent to the descending solids. 生产时，还原气通过位于还原带底部的环形风管进入到还原炉内，迎着下降炉料向上运动。The charge solids flow continuously into the top of the furnace through seal legs. 固体炉料通料封管不断从竖炉顶部进入。The reduction furnace is designed for uniform mass movement of the burdn by gravity feed, through the preheating, reduction, and cooling zones of the furnace. 还原炉的设计使得炉料能够依靠自身的重力作用均匀地通过预热带、还原带、冷却带。The cooled DRI is continuously discharged through seal legs at the bottom of the furnace. 冷却后的直接还原铁可以不断地通过炉底料封管排出。Cooling gases flow countercurrent to the burden in the cooling zone of the shaft furnace. 冷却气体的流向与竖炉内冷却带炉料的流向相反。The reducing top gas flows from an outlet pipe into the top-gas scrubber where it is cooled and its dust particles are removed. 从炉顶逸出的气体流向洗涤器，在那里冷却，洗涤除去炉尘。The largest portion of the top gas is recompressed, edriched with natural gas, preheated to about 400o C, and piped into the reformer tubes. In the catalyst tubes, the gas mixture is reformed to carbon monoxide and hydrogen. The hot reformed gas is then recycled to the DR furnace. 大部分炉顶气体被压缩后与天然气混合预热到约400o C，导入重整管，被重整成一氧化碳和氢气，然后循环到直接还原炉内。

(2) reduction processes with solid reducing agents （2）固体还原法

The solid reducing agents are coals of any granulation and composition in direct reduction processes. 固体还原法使用的还原剂是呈粒化状态的煤和合成的煤。Rotary kiln furnace is important equipment used solid reducing agents. This process operates in a continuously materials flow. 回转窑是使用固体还原剂的重要设备，这个工艺是连续生产的。The mature processes in coal-based direct reduction are German SL/RN process, british DRC process and French Codir process. 目前，煤基直接还原流程成熟的工艺是德国的SL/RN法，英国的DRC 法和法国的Codir 法。

The outcome of all direct reduction techniques is sponge iron. 直接还原去的产品是海绵铁，It derives its name from its appearance of high porosity. 这名字的产生是源于它表面的多孔性。Sponge iron is exposed to the hazard of reoxidation during handling and storage unless corresponding measures are adopted. 如果不采取相应的措施，海绵铁在处理和贮存过程中就面临重新氧化的危险。Reoxidation can be prevented by hot briquetting, the application of a “lime shell” or passivation with water glass. 用热压成块，外层喷涂石灰或水玻璃钝化可以阻止再氧化。

2.Smelting reduction technology 2.熔融还原技术

Smelting reduction tehnology usually produces hot metal from ore without coke. 熔融还原法是指不用焦炭从矿石中还原液态铁水的方法。This reduction process can be subdivided into two main groups: melter gasifiers and iron bath reactors. 熔融还原法主要有两种工艺：熔融气化炉法和铁浴反应炉法。In melter gasifiers processes, the COREX process which are developed together by the V oest Alpine and German Korf has gone into production. 熔融气化炉工艺中由奥钢联(V oest Alpine)与德国科尔夫（Korf）公司共同开发的COREX 法已经用于工业生产。

Smelting reduction together with direct reduction techniques represent a significant expansion of the alternatives to classical blast furnace processes. 熔融还原和直接还原一起代表了传统高炉工艺的重要发局趋势。

Raw Materials of Steelmaking 炼钢原料

The hot metal tapped from the blast furnace is the principal raw materials used for steelmaking. Besides hot metal, further charge materials are: steel scrap, sponge iron, slag formers, alloying agents and oxidizing agents.用于炼钢的主要原料是高炉铁水，此外，还有废钢、海绵铁、造渣剂、合金剂和氧化剂。

1. Blast furnace iron(Hot metal )1．高炉铁水

Blast furnace iron consists of the element iron combined with numerous other chemical elements the most common of which are carbon, manganese, phosphorus, sulphur, and silicon. 铁水是由铁及其他化学元素组成的，最常见的元素有碳、锰、磷、硫和硅。Pig iron may contain 3.0 to 4.5 per cent of carbon, 0.15 to 2.5 per cent or more of manganese, 0.02 to 0.06 per cent of sulphur, 0.3 per cent or more silicon and small amount of phosphorous. 生铁可能含有3％～4.5％的碳，0.05％～2.5％的锰，0.02％～0.06％的硫，0.3％或更多的硅和少量的磷。Large quantities of tramp elements within the hot metal still have to be removed partly or completely. 铁水中大量的杂质元素必须部分或全部除去，In fact, this is a most important task of steelmaking. 事实上，这就是炼钢的主要任务。

2.Steel scrap and sponge iron 2．废钢和海绵铁

Scrap and sponge iron can be used as iron supplier and cooling agent. 废钢或海绵铁也可以作为炼钢的原料和冷却剂来使用。

Worldwide, scrap participates 40 per cent in steel production input and must there fore be considered as an important raw material. 在世界范围内，废钢占炼钢原料的40％，所以它是一种重要的原料。Its use in steelmaking waries, depending on the production process applied. 废钢的用量根据炼钢生产工艺的不同而变化。In BOF, scrap accounts for about 20 per cent, while in electric are furnace, it may be 100 per cent. 在碱性氧气转炉炼钢过程中，废钢量约占20％，而电炉生产中，它可以占100％。

Steel scrap may be classified according to its sources:按照来源废钢可以分为以下几类：

Circulating scrap循环废钢This arises during the steelmaking and rolling process in a given works. 循环废钢是在钢铁厂的炼钢和轧钢过程中产生的。It consists of sheared ends and rejected materials which is normally returned immediately to the steelmaking vessel. 循环废钢以各种切头和废品形式存在，通常会很快回到炼钢炉中。

Process scrap加工废钢This arises at the customer’s works during the manufacture of finished articles. It is usually returned quickly to the steelmaking plants.它是用户制造成品时产生的，通常会很快返回到钢厂。

Capital scrap基建废钢This arises from scrapping manufactured goods and equipment. 它来源于报废的商品及设备。In some cases it may be returned to the works after three or four years’use, or with heavy capital equipment the life may be fifty years or more, but the average appears to be about twenty years.在某些情况下，这些物质使用3～4年后可能又返回到厂里，而大型基建设备的寿命可能有50年或更多，但是它们的平均寿命大约20年。

Circulating and process scrap usually return to the steelmaker without contamination from undesirable elements, and heavy capital scrap is generally of the same quality. 循环废钢及加工废钢通常在没有被杂质元素污染的情况下返回到钢厂，大型基建废钢也具有同样的质量。Much “short life” capital scrap contaminated with coatings of various kinds is returned, without the complete separation of non-ferrous

components in the form of pressed bundles. This gives a sharp increase in the residuals in the steel, which detracts from its properties for a number of applications.许多寿命短的基建废钢则由于受到各种涂层的污染，在没有完全与非铁成分分离的情况下以打包的形式返回，这使钢中的杂质含量急剧增加，降低了钢的很多使用性能。

In fact, scrap must first be sorted and the impurities elements, e.g. non-ferrous metals, removed in special dressing plants. 实际上，废钢必须首先分类，而那些不需要的杂质元素，例如，非铁金属必须在特殊的选矿厂去除。Nowadays this is frequently done in modern pressing and crushing or shredding equipment using the various kinds of scrap(e.g. loose scrap, chips, shredding ) helps to promote recycling.目前，这个工作通常用现代的冲压、破碎和切割设备来完成。使用各种商业废钢(如：粗钢、废钢片、钢屑)有助于促进其循环利用。

Sponge iron provided the main source of iron and steel for many centuries before the blast furnace was developed around 1300 A.D. 海绵铁在公元1300年人类发明高炉之前的几个世纪里一直是钢铁的主要来源。In its modern usage, sponge iron is referred to as direct-reduced iron(DRI). 现在的应用中，海绵铁是指直接还原铁。Today, the major portion of DRI production is used as a substitute for scrap in the electric are steelmaking furnace (EAF). 大部分直接还原铁用来代替电弧炉中的废钢。DRI derived from virgin iron ore units is a relatively pure material with dilutes contaminants in the scrap and improves the steel quality.由天然铁矿石冶炼而成的直接还原铁是一种相对纯净的产品，它的杂质比废钢中的少，从而提高了钢的质量。

3.Slsg formers 3．造渣剂

Just as in the case of the hot metal, the slag formers are used to produce a reactionable low viscosity slag capable of absorbing undesired elements. 就如铁水的(生产)情况一样，使用造渣剂会产生一种反应性好的能吸收杂质元素的低黏度炉渣。Slag formers are used at all stages of iron and steel production, such as refining, pretreatment, post-treatment, and in steel casting. 在钢铁生产的各个阶段，如精炼阶段、预处理阶段、炉外精炼阶段以及铸钢阶段都使用造渣剂。

Slag formers consist of lime, dolomite, fluorspar, etc. 造渣剂由石灰、白云石、萤石等组成的。Lime (CaO) and dolomite (CaCO3,MgCO3) are the two primary fluxes. Lime is obtained by calcining the carbonate minerals in rotary kilns. Some typical analyses are as followes:石灰和白云石是两种主要的造渣剂，石灰可以通过在回转窑内煅烧碳酸盐获得。造渣剂的一些典型的分析如下。

As slag formers, a special limitation is that dusty materials must be avoided, since dust is carried off easily by waste gases. 作为造渣剂要特别注意避免使用粉末状材料，因为废气很容易将粉末带走。

4.Alloying agents and deoxidizing agents 4．合金剂和脱氧剂

The steel also has to possess certain properties obtained by varying defined amounts of alloying agents. These properties might be, for example, corrosion resistance, machinability, strength at elevated temperatures.只有使用不同种类和数量的合金剂，钢才能拥有某些性能。例如耐腐蚀性、可加工性和高温强度。

The important alloying agents used in the production of steel are nickel, ferrochromium, ferrotitanium, ferrotungsten, ferrovanadium, ferrosilicon, and ferromolybdenum, etc.用于炼钢的重要合金剂是镍、铬铁、钛铁、钨铁、钒铁、硅铁和钼铁等。

The deoxidizing agents—the additions for binding the oxygen dissolved in the

liquid steel—are often added immediately after the refining process. They are usually classified among the alloying additions.脱氧剂，即与液态钢中溶解的氧进行结合的添加物常常是在精炼之后立即加入，它们常归于合金剂一类。

5.Oxidizing agents 5．氧化剂

Oxidizing agents consist of oxygen, iron ores and scale, etc. They play the most important role in the production of steel. 氧化剂包括氧气、铁矿石和氧化铁皮等，它们在炼钢过程中起着非常重要的作用。

Steels of types钢的分类

Steel grades can be subdivided according to chemical composition and service properties. According to chemical composition there are plain carbon steels and alloy steels. 钢可以根据化学成分和用途进行分类。按照化学成分，钢被分为普碳钢和合金钢两种。

1.Plain carbon steel 1．普碳钢

Steel theoretically is an alloy of iron and carbon. 从理论上讲，钢是一种铁和碳的合金。When produced commercially, however, certain other elements-notably manganese, phosphorus, sulfur, and silicon are present in small quantities. 但是在商业生产时，其他元素特别是锰、磷、硫和硅也少量存在。When these four foreign elements are present in their normal percentages, the product is referred to as plain-carbon steel. 当这四种杂质元素以通常的比例存在时，这一产品就称为普碳钢。Its strength is primarily a function of its carbon content. The higher the carbon content, the higher the tensile strength and the greater the hardness to which the steel may be heat-treated. 普碳钢的强度主要随碳含量的变化而变化，碳含量越高，抗拉强度就越高，并且热处理后所达到的硬度也越高。Unfortunately, the ductility of plain-carbon steel decreases as the carbon content is increased, and its hardenability is quite low. 遗憾的是当碳含量增加时，它的延展性就降低，并且可淬性也很低。In addition, the properties of ordinary carbon steels are impaired by both high and low temperature, and they are subject to corrosion in most environments. 此外在过高和过低的温度之下，普碳钢的性能也降低，多数环境下，它们还容易受到腐蚀。

Plain-carbon steels are generally classed into three subgroups, based on carbon content.普碳钢按照碳含量高低一般被分为三类。Low-carbon steels have less than 0.30 per cent carbon, possess good form ability and weldability, but not enough hardnability to be hardened to any significant depth. 低碳钢的碳含量小于0.3％，拥有良好的可锻性和焊接性，但可淬性差，不能淬火到有效的程度。Their structures usually are ferrite and pearlite, and the material generally is used as it comes from the hot-forming or cold-forming process. 它们的结构通常是铁素体和珠光体，这种材料常在热轧和冷轧后使用。Low-carbon steels are usually used for low-strength parts requiring a great deal of forming. 低碳钢通常用来制造需要进行多次成形加工的低强度零件。Medium-carbon steels have between 0.3 and 0.60 per cent carbon, and they are used for forgings and other applications where increased strength and a certain amount of ductility are necessary. 中碳钢的碳含量在0.3％～0.6％之间，它们用于锻件以及制造另一些需要强度比较高，并具有一定韧性的部件。High-carbon steels have morethan 0.60 per cent carbon, toughness and formability are quite low, but hardness and wear resistance are high. 高碳钢含有超过0.6％的碳，它的韧性和可塑性相当低，但硬度和抗磨性高，剧烈淬火时可以形成马氏体，可淬性较差。Severe quenches can form martensite,

but hardenability is still poor. High-carbon steels are used for high-strength parts such as springs, tools, and dies. 高碳钢用来制造弹簧、刀具和模具等高强度零件。

Plain carbon steels are the lowest-cost steel material and should be considered for many applications. 普碳钢是价格最低的钢材，被认为有许多用途。Often, however, their limitations become restrictive. 但是它们的使用也受到限制。When improved material is required, steels can be upgraded by the addition of one or more alloying elements. 当需要提高材料的性能时，钢可以通过加入一种或多种合金元素升级。

2.Alloy steel 2．合金钢

Alloy steels are formed by the addition of one or more of the following elements: chromium, nickel, molybdenum, vanadium, tungsten, titanium, and copper, as well as manganese, silicon, and small amonunts of other alloying elements. 当(钢中)加进一种或几种元素时就可以制成合金钢，这些元素是：铬、镍、钼、钒、钨、钛、硼、铜、锰、硅和少量别的合金元素。Alloy steels are divided into two types: low alloy steels with under 10 per cent of added elements and high alloy steels with over 10 per cent (usually between 15 and 30 per cent ) of added elements.合金钢可以被分为两种类型：添加元素低于10％的低合金钢和高于10％的高合金钢(后者的添加元素一般在15％～30％之间)。

Alloy steels have special properties determined by the mixture and the amount of other metals added. Alloy elements are added to steel for the following basic purposes:合金钢之所以具有各种特殊的性能取决于所加进的金属的种类及其数量。加入钢中合金元素的作用如下：

Chromium铬Addition of chromium imparts hardness, strength wear resistance, heat resistance, and corrosion resistance to steels. 加铬能提高钢的硬度、强度、耐磨性、耐热性和耐腐蚀性能。In 1913 Harry Brearley of Sheffield was experimenting with alloy steels for gun barrels, and among the samples which he threw aside as being unsuitable was one containing about 14 kercent of chromium . 1913年，设菲尔德的哈里??布雷尔利试用合金钢做枪筒，在他认为不适用而丢在一边的试样当中，有一种含铬14％的钢。Some months later he noticed that most of the steels had rusted, but the chromium steel remained bright. 数月之后，他发现大多数钢都生锈了，而这种铬钢还保持着它的光泽。This led to the development of stainless steels. 这就导致了不锈钢的发展。Chromium alloys are commonly used in axles, bolts, springs, and studs for automobiles. 铬合金钢常常用来制造轮轴、螺栓、弹簧和用于机动车的双头螺栓。They are also used in tool steel for chisels dies, drills, files, knives, and shears.它们也可以作为工具钢制作模具、凿子、钻头、锉刀、剪刀。

Nickel镍Nickel is one of the oldest and most common of alloy elements the addition of nickel increases strength, yield point, hardness, and ductility. It also increases the depth of hardening. 镍是最古老和最常用的合金元素之一。加镍不但能提高强度、屈服点、硬度和韧性，而且能够增加淬透层深度。Nickel increases corrosion resistance and is one of the major constituents of the “stainless” or corrosion-resisting steels. 镍能够提高耐蚀性，因此它是不锈钢或耐蚀钢的主要成分之一。Nickel steels have be used for components in automobiles and other vehicles, including aircraft, and for a multitude of components such as gears, shafting which require great strength, and other heavy duty products.镍钢可以被用来制造汽车、其他运载工具包括飞机，以及大量高强度齿轮、轴系部件和其他重型产品。

Molybdenum钼Molybdenum, uneven in extremely small amounts, has

considerable effect as an alloying element on the physical properties of steels. Molybdenum improves strength, hardenability, and wear resistance. Molybdenum steels are readily heat-treated, forged and machined.钼作为一种合金元素，即使是微量都能对钢的物理性质产生很大的影响。钼能提高强度、硬度和耐磨性。钼钢益于热处理锻造和机加工。

Vanadium钒Vanadium is usually used in amounts of less than 0.25 per cent. 钒的使用含量通常少于0.25％。As an alloying agent, vanadium improves fatigue strength, ultimate strength, yield point, toughness, and resistance to impact and vibration. 作为一种合金元素，钒能提高疲劳强度、极限强度、屈服点、韧性、冲击强度和抗振能力。Chromium-vanadium steels have good ductility and high strength. 铬钒钢具有很好的韧性和很高的强度。They are widely used in heavy forgings, axles, springs, and tools, depending upon their carbon content. 根据含碳量的不同，它们广泛地被用于大型铸件、轮轴、弹簧和工具上。

Tungsten钨Tungsten is used largely with chromium as a high-speed toll steel which contains 14.00 to 18.00 per cent tungsten and 2.00 to 4.00 per cent ehromium. 钨主要和铬一起用作高速工具钢的元素，这种钢的含钨量为14.00％～18.00％，含铬量为2.00％～4.00％。This steel processes the characteristic of being able to retain a sharp cutting-edge even though heated to redness in cutting. 高速工具钢具有这样的特性：切削时即使加热到发红的程度，刀刃仍能保持很锋利。

Titanium钛Titanium helps to improves strength, hardenalility, and wear resistance.钛有助于提高强度、硬度和耐磨性。

Copper铜The addition of copper increase corrosion resistance, and improves machinability.加入铜能增强耐蚀性，改善力学性能。

Manganese锰Manganese helps to reduce certain undesirable effects of sulphur by combining with the sulphur. It also combines with carbon to increase hardness and toughness. 锰用来同硫化合有助于降低硫的某些不良影响，也可以同碳化合用于增加硬度和韧性。Manganese processes the property of aiding in increasing the depth of hardness penetration. 锰具有增加淬硬层深度的性能。It also improves the forging qualities by reducing brittleness at rolling and forging temperatures. 锰还能降低轧制和锻造时的脆性以改善锻造质量。Manganese alloys are used mostly for making axles, forgings, gears, shafts, and gun barrels. 锰合金钢常用来制造轮轴、锻件、齿轮、传动轴和枪管等。

Silicon硅 A small amounts of silicon improves ductility. 少量的硅能改善韧性。It is used largely to increase impact resistance when combined with other alloys. 硅主要是与其他合金元素化合提高抗冲击强度。

Iron and Steel

●1.The earth contains a large number of metals which are useful to man.地球上含有很多对人类很有用的金属。2.One of the most important of these is iron.其中最重要的是铁。3.Modern industry needs considerable quantities of this metal, either in the form of iron or in the form of steel.现代工业需要大量的这样的金属，无论是铁的形式还是钢的形式。4.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.一定数量的有色金属，包括铝和锌，也很重要，但是即使今天，我们的大多数的工程产品是铁或钢。5.Moreover, iron possesses magnetic properties, which have made the development of electrical power possible.此外，铁具有磁性，使电力的发展成为可能。

●1.The iron ore which we find on earth is not pure.我们在地球上发现的铁矿石并不是纯净的。

2.It contains some impurities that must be removed by smelting.它含有一些杂质必须用熔炼来除去。

3.The process of smelting consists of heating the ore in a blast furnace with coke and limestone, and reducing it to metal.熔炼过程包括将矿石和焦炭和石灰石一起放入高炉加热，还原金属。

4.Blasts of hot air enter the furnace from the bottom and provide the oxygen that is necessary for the reduction of the ore.热空气从底部冲入以提供还原矿石需要的氧气。

5.The ore becomes molten , and its oxides combine with carbon from the coke.矿石熔化，它的氧化物与焦炭中的碳结合。

6.The non-metallic constituents of the ore combine with the limestone to form a liquid slag.矿石中的非金属成分以液渣的形式与石灰石与结合。

7.This floats on top of the molten iron, and passes out of the furnace through a tap.这些漂浮在熔融铁上的物质，通过旋塞从熔炉中排出。

8.The metal which remains is pig iron.遗留下来的金属就是生铁。

●1.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.我们可以将它在另一个圆顶高炉里和更多的焦炭和石灰石一起再一次熔化，将它流进一个长柄大勺中或是直接浇进模子里。2.It is brittle and may fracture under tension.它的脆性，在应力下会折断。3.But it possesses certain properties that make it very useful in the manufacture of machinery.但是它拥有的这一属性使它在机械制造上很有用。4.In the molten state it is very fluid, therefore, it is easy to cast it into intricate shapes.在

熔融状态下它是流畅的，因此，它很容易浇铸成复杂的形状。5.Also it is easy to machine it.而且也很容易加工。6.Cast iron contains small proportions of other substances.铸铁包含一小比例的其他物质。7.These non-metallic constituents of cast iron include carbon, silicon and sulphur, and the presence of these substances affects the behavior of the mental, iron which contains a negligible quantity of carbon, for example, wrought iron behaves differently from iron which contains a lot of carbon.这些铸铁中的非金属成分影响了金属的表现，比如，含有微量的碳的铁，与含有很多碳的铸铁表现很不同。

●1.The carbon in cast iron is present partly as free graphite and partly as chemical combination of iron and carbon which is called cementite.铸铁中的碳一部分代表游离的石墨，一部分代表称为铁素体的碳铁化学结合物。2.This is a very hard substance, and it makes the iron hard too.这是非常坚硬的物质，它使铁也变得坚硬。3.However, iron can only hold about 1.5% of cementite. 然而，铁只能容纳大概1.5%的铁素体。4.Any carbon content above that percentage is present of the form of flaky graphite.任何超过这个百分含量就代表薄片石墨的形式。5.Steel contains no free graphite, and its carbon content ranges from almost nothing to 1.5%.钢不含游离石墨，它的碳含量从几乎为零到1.5%。6.we make wire and tubing from mild steel with very low carbon content, and drills and cutting tools from high carbon.我们用含碳量和少的低碳钢制造电线、管形材料，用高碳钢制造钻头和切割工具。