机械专业英语中英

第一篇：机械专业英语中英

机械专业英语词汇中英文对照

机床 machine tool

金属工艺学 technology of metals刀具 cutter摩擦 friction联结 link

传动 drive/transmission轴 shaft弹性 elasticity

频率特性 frequency characteristic误差 error响应 response定位 allocation机床夹具 jig动力学 dynamic运动学 kinematic静力学 static

分析力学 analyse mechanics拉伸 pulling压缩 hitting剪切 shear扭转 twist

弯曲应力 bending stress

强度 intensity

三相交流电 three-phase AC磁路 magnetic circles变压器 transformer

异步电动机 asynchronous motor几何形状 geometrical精度 precision正弦形的 sinusoid交流电路 AC circuit

机械加工余量 machining allowance变形力 deforming force变形 deformation应力 stress硬度 rigidity热处理 heat treatment退火 anneal正火 normalizing脱碳 decarburization渗碳 carburization电路 circuit

半导体元件 semiconductor element反馈 feedback

发生器 generator

直流电源 DC electrical source门电路 gate circuit逻辑代数 logic algebra

外圆磨削 external grinding内圆磨削 internal grinding平面磨削 plane grinding变速箱 gearbox离合器 clutch绞孔 fraising绞刀 reamer

螺纹加工 thread processing螺钉 screw铣削 mill

铣刀 milling cutter功率 power工件 workpiece

齿轮加工 gear mechining齿轮 gear

主运动 main movement

主运动方向 direction of main movement进给方向 direction of feed

进给运动 feed movement

合成进给运动 resultant movement of feed合成切削运动 resultant movement of cutting

合成切削运动方向 direction of resultant

movement of cutting切削深度 cutting depth前刀面 rake face刀尖 nose of tool前角 rake angle后角 clearance angle龙门刨削 planing主轴 spindle主轴箱 headstock卡盘 chuck

加工中心 machining center车刀 lathe tool车床 lathe钻削 镗削 bore车削 turning磨床 grinder基准 benchmark钳工 locksmith

锻 forge压模 stamping焊 weld

拉床 broaching machine拉孔 broaching装配 assembling铸造 found

流体动力学 fluid dynamics流体力学 fluid mechanics加工 machining

液压 hydraulic pressure切线 tangent

机电一体化 mechanotronics mechanical-electrical integration

气压 air pressure pneumatic pressure

稳定性 stability

介质 medium

液压驱动泵 fluid clutch

液压泵 hydraulic pump

阀门 valve

失效 invalidation

强度 intensity

载荷 load

应力 stress

安全系数 safty factor可靠性 reliability螺纹 thread螺旋 helix键 spline销 pin

滚动轴承 rolling bearing滑动轴承 sliding bearing弹簧 spring

制动器 arrester brake十字结联轴节 crosshead联轴器 coupling链 chain

皮带 strap

精加工 finish machining

粗加工 rough machining

变速箱体 gearbox casing

腐蚀 rust

氧化 oxidation

磨损 wear

耐用度 durability

随机信号 random signal离散信号 discrete signal超声传感器 ultrasonic sensor

第二篇：机械专业英语文章 中英文对照

Types of Materials 材料的类型

Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic (once living) and inorganic (never living) materials. 材料可以按多种方法分类。科学家常根据状态将材料分为：固体、液体或气体。他们也把材料分为有机材料(曾经有生命的)和无机材料(从未有生命的)。

For industrial purposes, materials are divided into engineering materials or nonengineering materials. Engineering materials are those used in manufacture and become parts of products. 就工业效用而言，材料被分为工程材料和非工程材料。那些用于加工制造并成为产品组成部分的就是工程材料。

Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product. 非工程材料则是化学品、燃料、润滑剂以及其它用于加工制造过程但不成为产品组成部分的材料。

Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc.

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工程材料还能进一步细分为：①金属材料②陶瓷材料③复合材料 ④聚合材料，等等。

Metals and Metal Alloys 金属和金属合金

Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility. 金属就是通常具有良好导电性和导热性的元素。许多金属具有高强度、高硬度以及良好的延展性。

Some metals, such as iron, cobalt and nickel, are magnetic. At low temperatures, some

metals

and

intermetallic

compounds

become superconductors. 某些金属能被磁化，例如铁、钴和镍。在极低的温度下，某些金属和金属化合物能转变成超导体。

What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table. Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans. 合金与纯金属的区别是什么?纯金属是在元素周期表中占据特定位置的元素。

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例如电线中的铜和制造烹饪箔及饮料罐的铝。

Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold and nickel. 合金包含不止一种金属元素。合金的性质能通过改变其中存在的元素而改变。金属合金的例子有：不锈钢是一种铁、镍、铬的合金，以及金饰品通常含有金镍合金。

Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio. 为什么要使用金属和合金?许多金属和合金具有高密度，因此被用在需要较高质量体积比的场合。

Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy. Many alloys also have high fracture toughness, which means they can withstand impact and are durable. 某些金属合金，例如铝基合金，其密度低，可用于航空航天以节约燃料。许多合金还具有高断裂韧性，这意味着它们能经得起冲击并且是耐用的

What are some important properties of metals?

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Density is defined as a material’s mass divided by its volume. Most metals have relatively high densities, especially compared to polymers. 金属有哪些重要特性?

密度定义为材料的质量与其体积之比。大多数金属密度相对较高，尤其是和聚合物相比较而言。

Materials with high densities often contain atoms with high atomic numbers, such as gold or lead. However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight. 高密度材料通常由较大原子序数原子构成，例如金和铅。然而，诸如铝和镁之类的一些金属则具有低密度，并被用于既需要金属特性又要求重量轻的场合。

Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced. Metals can generally contain nicks and dents without weakening very much, and are impact resistant. A football player counts on this when he trusts that his facemask won’t shatter. 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。

Plastic deformation is the ability of bend or deform before breaking.

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As engineers, we usually design materials so that they don’t deform under normal conditions. You don’t want your car to lean to 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自己的汽车向东倾斜。

However, sometimes we can take advantage of plastic deformation. The crumple zones in a car absorb energy by undergoing plastic deformation before they break. 然而，有时我们也能利用塑性变形。汽车上压皱的区域在它们断裂前通过经历塑性变形来吸收能量。

The atomic bonding of metals also affects their properties. In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere. Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires. 金属的原子连结对它们的特性也有影响。在金属内部，原子的外层阶电子由所有原子共享并能到处自由移动。由于电子能导热和导电，所以用金属可以制造好的烹饪锅和电线。

It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal. No photons pass through. 因为这些阶电子吸收到达金属的光子，所以透过金属不可能看得见。没有光子

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能通过金属。

Alloys are compounds consisting of more than one metal. Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation. 合金是由一种以上金属组成的混合物。加一些其它金属能影响密度、强度、断裂韧性、塑性变形、导电性以及环境侵蚀。

For example, adding a small amount of iron to aluminum will make it stronger. Also, adding some chromium to steel will slow the rusting process, but will make it more brittle. 例如，往铝里加少量铁可使其更强。同样，在钢里加一些铬能减缓它的生锈过程，但也将使它更脆。

Ceramics and Glasses 陶瓷和玻璃

A ceramic is often broadly defined as any inorganic nonmetallic material. By this definition, ceramic materials would also include glasses; however, many materials scientists add the stipulation that “ceramic” must also be crystalline. 陶瓷通常被概括地定义为无机的非金属材料。照此定义，陶瓷材料也应包括玻璃;然而许多材料科学家添加了“陶瓷”必须同时是晶体物组成的约定。

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A glass is an inorganic nonmetallic material that does not have a crystalline structure. Such materials are said to be amorphous. 玻璃是没有晶体状结构的无机非金属材料。这种材料被称为非结晶质材料。 Properties of Ceramics and Glasses Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance. 陶瓷和玻璃的特性

高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和抗腐蚀性是陶瓷和玻璃的一些有用特性。

Many ceramics are good electrical and thermal insulators. Some ceramics have special properties: some ceramics are magnetic materials; some are piezoelectric materials; and a few special ceramics are superconductors at very low temperatures. Ceramics and glasses have one major drawback: they are brittle. 许多陶瓷都是电和热的良绝缘体。某些陶瓷还具有一些特殊性能：有些是磁性材料，有些是压电材料，还有些特殊陶瓷在极低温度下是超导体。陶瓷和玻璃都有一个主要的缺点：它们容易破碎。

Ceramics are not typically formed from the melt. This is because most

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ceramics will crack extensively (i.e. form a powder) upon cooling from the liquid state. 陶瓷一般不是由熔化形成的。因为大多数陶瓷在从液态冷却时将会完全破碎(即形成粉末)。

Hence, all the simple and efficient manufacturing techniques used for glass production such as casting and blowing, which involve the molten state, cannot be used for the production of crystalline ceramics. Instead, “sintering” or “firing” is the process typically used.

因此，所有用于玻璃生产的简单有效的—诸如浇铸和吹制这些涉及熔化的技术都不能用于由晶体物组成的陶瓷的生产。作为替代，一般采用“烧结”或“焙烧”工艺。

In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point. At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained. 在烧结过程中，陶瓷粉末先挤压成型然后加热到略低于熔点温度。在这样的温度下，粉末内部起反应去除孔隙并得到十分致密的物品。

An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core

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glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage. 光导纤维有三层：核心由高折射指数高纯光传输玻璃制成，中间层为低折射指数玻璃，是保护核心玻璃表面不被擦伤和完整性不被破坏的所谓覆层，外层是聚合物护套，用于保护光导纤维不受损。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light. 为了使核心玻璃有比覆层大的折射指数，在其中掺入微小的、可控数量的能减缓光速而不会吸收光线的杂质或搀杂剂。

Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle. 由于核心玻璃的折射指数比覆层大，只要在全内反射过程中光线照射核心/覆层分界面的角度比临界角大，在核心玻璃中传送的光线将仍保留在核心玻璃中。

The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.

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全内反射现象与核心玻璃的高纯度一样，使光线几乎无强度损耗传递长距离成为可能。

Composites 复合材料

Composites are formed from two or more types of materials. Examples include polymer/ceramic and metal/ceramic composites. Composites are used because overall properties of the composites are superior to those of the individual components. 复合材料由两种或更多材料构成。例子有聚合物/陶瓷和金属/陶瓷复合材料。之所以使用复合材料是因为其全面性能优于组成部分单独的性能。

For example: polymer/ceramic composites have a greater modulus than the polymer component, but aren’t as brittle as ceramics.

Two types of composites are: fiber-reinforced composites and particle-reinforced composites. 例如：聚合物/陶瓷复合材料具有比聚合物成分更大的模量，但又不像陶瓷那样易碎。

复合材料有两种：纤维加强型复合材料和微粒加强型复合材料。 Fiber-reinforced Composites Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers

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increase the modulus of the matrix material. 纤维加强型复合材料

加强纤维可以是金属、陶瓷、玻璃或是已变成石墨的被称为碳纤维的聚合物。纤维能加强基材的模量。

The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved. 沿着纤维长度有很强结合力的共价结合在这个方向上给予复合材料很高的模量，因为要损坏或拉伸纤维就必须破坏或移除这种结合。

Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive. 把纤维放入复合材料较困难，这使得制造纤维加强型复合材料相对昂贵。 Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment, such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix. 纤维加强型复合材料用于某些最先进也是最昂贵的运动设备，例如计时赛竞赛用自行车骨架就是用含碳纤维的热固塑料基材制成的。

Body parts of race cars and some automobiles are composites made of glass fibers (or fiberglass) in a thermoset matrix.

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竞赛用汽车和某些机动车的车体部件是由含玻璃纤维(或玻璃丝)的热固塑料基材制成的。

Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis. Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus. 纤维在沿着其轴向有很高的模量，但垂直于其轴向的模量却较低。纤维复合材料的制造者往往旋转纤维层以防模量产生方向变化。

Particle-reinforced composites Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black. 微粒加强型复合材料[番茄用户1] [番茄用户2] [番茄用户3] [番茄用户4] [番茄用户5] [番茄用户6] 用于加强的微粒包含了陶瓷和玻璃之类的矿物微粒，铝之类的金属微粒以及包括聚合物和碳黑的非结晶质微粒。

Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix. An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer.

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微粒用于增加基材的模量、减少基材的渗透性和延展性。微粒加强型复合材料的一个例子是机动车胎，它就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。

Polymers 聚合材料

A polymer has a repeating structure, usually based on a carbon backbone. The repeating structure results in large chainlike molecules. Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive. 聚合物具有一般是基于碳链的重复结构。这种重复结构产生链状大分子。由于重量轻、耐腐蚀、容易在较低温度下加工并且通常较便宜，聚合物是很有用的。

Some important characteristics of polymers include their size (or molecular weight), softening and melting points, crystallinity, and structure. The mechanical properties of polymers generally include low strength and high toughness. Their strength is often improved using reinforced composite structures. 聚合材料具有一些重要特性，包括尺寸(或分子量)、软化及熔化点、结晶度和结构。聚合材料的机械性能一般表现为低强度和高韧性。它们的强度通常可采用加强复合结构来改善。

Important Characteristics of Polymers Size. Single polymer molecules typically have molecular weights between 10,000 and 1,000,000g/mol—that can be more than 2,000 repeating units

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depending on the polymer structure! 聚合材料的重要特性

尺寸：单个聚合物分子一般分子量为10,000到1,000,000g/mol之间，具体取决于聚合物的结构—这可以比2,000个重复单元还多。

The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights. 聚合物的分子量极大地影响其机械性能，分子量越大，工程性能也越好。 Thermal transitions. The softening point (glass transition temperature) and the melting point of a polymer will determine which it will be suitable for applications. These temperatures usually determine the upper limit for which a polymer can be used. 热转换性：聚合物的软化点(玻璃状转化温度)和熔化点决定了它是否适合应用。这些温度通常决定聚合物能否使用的上限。

For example, many industrially important polymers have glass transition temperatures near the boiling point of water (100℃, 212℉), and they are most useful for room temperature applications. Some specially engineered polymers can withstand temperatures as high as 300℃(572℉).

例如，许多工业上的重要聚合物其玻璃状转化温度接近水的沸点(100℃,

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212℉)，它们被广泛用于室温下。而某些特别制造的聚合物能经受住高达300℃(572℉)的温度。

Crystallinity. Polymers can be crystalline or amorphous, but they usually have a combination of crystalline and amorphous structures (semi-crystalline). 结晶度：聚合物可以是晶体状的或非结晶质的，但它们通常是晶体状和非结晶质结构的结合物(半晶体)。

Interchain interactions. The polymer chains can be free to slide past one another (thermo-plastic) or they can be connected to each other with crosslinks (thermoset or elastomer). Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable. 原子链间的相互作用：聚合物的原子链可以自由地彼此滑动(热可塑性)或通过交键互相连接(热固性或弹性)。热可塑性材料可以重新形成和循环使用，而热固性与弹性材料则是不能再使用的。

Intrachain structure. The chemical structure of the chains also has a tremendous effect on the properties. Depending on the structure the polymer may be hydrophilic or hydrophobic (likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive. 链内结构：原子链的化学结构对性能也有很大影响。根据各自的结构不同，聚合物可以是亲水的或憎水的(喜欢或讨厌水)、硬的或软的、晶体状的或非结晶质的、

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易起反应的或不易起反应的。

The understanding of heat treatment is embraced by the broader study of metallurgy. Metallurgy is the physics, chemistry, and engineering related to metals from ore extraction to the final product. 对热处理的理解包含于对冶金学较广泛的研究。冶金学是物理学、化学和涉及金属从矿石提炼到最后产物的工程学。

Heat treatment is the operation of heating and cooling a metal in its solid state to change its physical properties. According to the procedure used, steel can be hardened to resist cutting action and abrasion, or it can be softened to permit machining. 热处理是将金属在固态加热和冷却以改变其物理性能的操作。按所采用的步骤，钢可以通过硬化来抵抗切削和磨损，也可以通过软化来允许机加工。

With the proper heat treatment internal stresses may be removed, grain size reduced, toughness increased, or a hard surface produced on a ductile interior. The analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties. 使用合适的热处理可以去除内应力、细化晶粒、增加韧性或在柔软材料上覆盖坚硬的表面。因为某些元素(尤其是碳)的微小百分比极大地影响物理性能，所以必须知道对钢的分析。

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Alloy steel owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium, manganese, molybdenum, tungsten, silicon, vanadium, and copper. Because of their improved physical properties they are used commercially in many ways not possible with carbon steels. 合金钢的性质取决于其所含有的除碳以外的一种或多种元素，如镍、铬、锰、钼、钨、硅、钒和铜。由于合金钢改善的物理性能，它们被大量使用在许多碳钢不适用的地方。

The following discussion applies principally to the heat treatment of ordinary commercial steels known as plain carbon steels. With this process the rate of cooling is the controlling factor, rapid cooling from above the critical range results in hard structure, whereas very slow cooling produces the opposite effect. 下列讨论主要针对被称为普通碳钢的工业用钢而言。热处理时冷却速率是控制要素，从高于临界温度快速冷却导致坚硬的组织结构，而缓慢冷却则产生相反效果。

A Simplified Iron-carbon Diagram 简化铁碳状态图

If we focus only on the materials normally known as steels, a simplified diagram is often used. 如果只把注意力集中于一般所说的钢上，经常要用到简化铁碳状态图。

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Those portions of the iron-carbon diagram near the delta region and those above 2% carbon content are of little importance to the engineer and are deleted. A simplified diagram, such as the one in Fig.2.1, focuses on the eutectoid region and is quite useful in understanding the properties and processing of steel. 铁碳状态图中靠近三角区和含碳量高于2%的那些部分对工程师而言不重要，因此将它们删除。如图2.1所示的简化铁碳状态图将焦点集中在共析区，这对理解钢的性能和处理是十分有用的。

The key transition described in this diagram is the decomposition of single-phase austenite(γ) to the two-phase ferrite plus carbide structure as temperature drops. 在此图中描述的关键转变是单相奥氏体(γ) 随着温度下降分解成两相铁素体加渗碳体组织结构。

Control of this reaction, which arises due to the drastically different carbon solubility of austenite and ferrite, enables a wide range of properties to be achieved through heat treatment. 控制这一由于奥氏体和铁素体的碳溶解性完全不同而产生的反应，使得通过热处理能获得很大范围的特性。

To begin to understand these processes, consider a steel of the eutectoid composition, 0.77% carbon, being slow cooled along line x-x’ in

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Fig.2.1. At the upper temperatures, only austenite is present, the 0.77% carbon being dissolved in solid solution with the iron. When the steel cools to 727℃(1341℉), several changes occur simultaneously.

为了理解这些过程，考虑含碳量为0.77%的共析钢，沿着图2.1的x-x’线慢慢冷却。在较高温度时，只存在奥氏体，0.77%的碳溶解在铁里形成固溶体。当钢冷却到727℃ (1341℉)时，将同时发生若干变化。

The iron wants to change from the FCC austenite structure to the BCC ferrite structure, but the ferrite can only contain 0.02% carbon in solid solution. 铁需要从面心立方体奥氏体结构转变为体心立方体铁素体结构，但是铁素体只能容纳固溶体状态的0.02%的碳。

The rejected carbon forms the carbon-rich cementite intermetallic with composition Fe3C. In essence, the net reaction at the eutectoid is austenite 0.77%C→ferrite 0.02%C+cementite 6.67%C.

被析出的碳与金属化合物Fe3C形成富碳的渗碳体。本质上，共析体的基本反应是奥氏体0.77%的碳→铁素体0.02%的碳+渗碳体6.67%的碳。

Since this chemical separation of the carbon component occurs entirely in the solid state, the resulting structure is a fine mechanical mixture of ferrite and cementite. Specimens prepared by polishing and etching in a weak solution of nitric acid and alcohol reveal the lamellar structure of

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alternating plates that forms on slow cooling. 由于这种碳成分的化学分离完全发生在固态中，产生的组织结构是一种细致的铁素体与渗碳体的机械混合物。通过打磨并在弱硝酸酒精溶液中蚀刻制备的样本显示出由缓慢冷却形成的交互层状的薄片结构。

This structure is composed of two distinct phases, but has its own set of characteristic properties and goes by the name pearlite, because of its resemblance to mother- of- pearl at low magnification. 这种结构由两种截然不同的状态组成，但它本身具有一系列特性，且因与低倍数放大时的珠母层有类同之处而被称为珠光体。

Steels having less than the eutectoid amount of carbon (less than 0.77%) are known as hypo-eutectoid steels. Consider now the transformation of such a material represented by cooling along line y-y’ in Fig.2.1.

含碳量少于共析体(低于0.77%)的钢称为亚共析钢。现在来看这种材料沿着图2.1中y-y’ 线冷却的转变情况。

At high temperatures, the material is entirely austenite, but upon cooling enters a region where the stable phases are ferrite and austenite. Tie-line and level-law calculations show that low-carbon ferrite nucleates and grows, leaving the remaining austenite richer in carbon. 在较高温度时，这种材料全部是奥氏体，但随着冷却就进入到铁素体和奥氏体稳定状态的区域。由截线及杠杆定律分析可知，低碳铁素体成核并长大，剩下含碳

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量高的奥氏体。

At 727℃(1341℉), the austenite is of eutectoid composition (0.77% carbon) and further cooling transforms the remaining austenite to pearlite. The resulting structure is a mixture of primary or pro-eutectoid ferrite (ferrite that formed above the eutectoid reaction) and regions of pearlite. 在727℃(1341℉)时，奥氏体为共析组成(含碳量0.77%)，再冷却剩余的奥氏体就转化为珠光体。作为结果的组织结构是初步的共析铁素体(在共析反应前的铁素体)和部分珠光体的混合物。

Hypereutectoid steels are steels that contain greater than the eutectoid amount of carbon. When such steel cools, as shown in z-z’ of Fig.2.1 the process is similar to the hypo-eutectoid case, except that the primary or pro-eutectoid phase is now cementite instead of ferrite. 过共析钢是含碳量大于共析量的钢。当这种钢冷却时，就像图2.1的z-z’线所示，除了初步的共析状态用渗碳体取代铁素体外，其余类似亚共析钢的情况。

As the carbon-rich phase forms, the remaining austenite decreases in carbon content, reaching the eutectoid composition at 727℃(1341℉). As before, any remaining austenite transforms to pearlite upon slow cooling through this temperature. 随着富碳部分的形成，剩余奥氏体含碳量减少，在727℃(1341℉)时达到共析组

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织。就像以前说的一样，当缓慢冷却到这温度时所有剩余奥氏体转化为珠光体。

It should be remembered that the transitions that have been described by the phase diagrams are for equilibrium conditions, which can be approximated by slow cooling. With slow heating, these transitions occur in the reverse manner. 应该记住由状态图描述的这种转化只适合于通过缓慢冷却的近似平衡条件。如果缓慢加热，则以相反的方式发生这种转化。

However, when alloys are cooled rapidly, entirely different results may be obtained, because sufficient time is not provided for the normal phase reactions to occur, in such cases, the phase diagram is no longer a useful tool for engineering analysis. 然而，当快速冷却合金时，可能得到完全不同的结果。因为没有足够的时间让正常的状态反应发生，在这种情况下对工程分析而言状态图不再是有用的工具。

Hardening 淬火

Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly. 淬火就是把钢件加热到或超过它的临界温度范围，然后使其快速冷却的过程。 If the carbon content of the steel is known, the proper temperature to which the steel should be heated may be obtained by reference to the iron-iron

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carbide phase diagram. However, if the composition of the steel is unknown, a little preliminary experimentation may be necessary to determine the range. 如果钢的含碳量已知，钢件合适的加热温度可参考铁碳合金状态图得到。然而当钢的成分不知道时，则需做一些预备试验来确定其温度范围。

A good procedure to follow is to heat-quench a number of small specimens of the steel at various temperatures and observe the result, either by hardness testing or by microscopic examination. When the correct temperature is obtained, there will be a marked change in hardness and other properties. 要遵循的合适步骤是将这种钢的一些小试件加热到不同的温度后淬火，再通过硬度试验或显微镜检查观测结果。一旦获得正确的温度，硬度和其它性能都将有明显的变化。

In any heat-treating operation the rate of heating is important. Heat flows from the exterior to the interior of steel at a definite rate. If the steel is heated too fast, the outside becomes hotter than the interior and uniform structure cannot be obtained. 在任何热处理作业中，加热的速率都是重要的。热量以一定的速率从钢的外部传导到内部。如果钢被加热得太快，其外部比内部热就不能得到均匀的组织结构。

If a piece is irregular in shape, a slow rate is all the more essential to eliminate warping and cracking. The heavier the section, the longer must be the heating time to achieve uniform results.

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如果工件形状不规则，为了消除翘曲和开裂最根本的是加热速率要缓慢。截面越厚，加热的时间就要越长才能达到均匀的结果。

Even after the correct temperature has been reached, the piece should be held at that temperature for a sufficient period of time to permit its thickest section to attain a uniform temperature. 即使加热到正确的温度后，工件也应在此温度下保持足够时间以让其最厚截面达到相同温度。

The hardness obtained from a given treatment depends on the quenching rate, the carbon content, and the work size. In alloy steels the kind and amount of alloying element influences only the hardenability (the ability of the workpiece to be hardened to depths) of the steel and does not affect the hardness except in unhardened or partially hardened steels. 通过给定的热处理所得到的硬度取决于淬火速率、含碳量和工件尺寸。除了非淬硬钢或部分淬硬钢外，合金钢中合金元素的种类及含量仅影响钢的淬透性(工件被硬化到深层的能力)而不影响硬度。

Steel with low carbon content will not respond appreciably to hardening treatment. As the carbon content in steel increases up to around 0.60%, the possible hardness obtainable also increases. 含碳量低的钢对淬火处理没有明显的反应。随着钢的含碳量增加到大约0.60%，可能得到的硬度也增加。

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Above this point the hardness can be increased only slightly, because steels above the eutectoid point are made up entirely of pearlite and cementite in the annealed state. Pearlite responds best to heat-treating operations; and steel composed mostly of pearlite can be transformed into a hard steel. 高于此点，由于超过共析点钢完全由珠光体和退火状态的渗碳体组成，硬度增加并不多。珠光体对热处理作业响应最好;基本由珠光体组成的钢能转化成硬质钢。

As the size of parts to be hardened increases, the surface hardness decreases somewhat even though all other conditions have remained the same. There is a limit to the rate of heat flow through steel. 即使所有其它条件保持不变，随着要淬火的零件尺寸的增加其表面硬度也会有所下降。热量在钢中的传导速率是有限的。

No matter how cool the quenching medium may be, if the heat inside a large piece cannot escape faster than a certain critical rate, there is a definite limit to the inside hardness. However, brine or water quenching is capable of rapidly bringing the surface of the quenched part to its own temperature and maintaining it at or close to this temperature. 无论淬火介质怎么冷，如果在大工件中的热量不能比特定的临界速率更快散发，那它内部硬度就会受到明确限制。然而盐水或水淬火能够将被淬零件的表面迅速冷却至本身温度并将其保持或接近此温度。

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Under these circumstances there would always be some finite depth of surface hardening regardless of size. This is not true in oil quenching, when the surface temperature may be high during the critical stages of quenching. 在这种情况下不管零件尺寸如何，其表面总归有一定深度被硬化。但油淬情况就不是如此，因为油淬时在淬火临界阶段零件表面的温度可能仍然很高。

Tempering 回火

Steel that has been hardened by rapid quenching is brittle and not suitable for most uses. By tempering or drawing, the hardness and brittleness may be reduced to the desired point for service conditions.

快速淬火硬化的钢是硬而易碎的，不适合大多数场合使用。通过回火，硬度和脆性可以降低到使用条件所需要的程度。

As these properties are reduced there is also a decrease in tensile strength and an increase in the ductility and toughness of the steel. The operation consists of reheating quench-hardened steel to some temperature below the critical range followed by any rate of cooling. 随着这些性能的降低，拉伸强度也降低而钢的延展性和韧性则会提高。回火作业包括将淬硬钢重新加热到低于临界范围的某一温度然后以任意速率冷却。

Although this process softens steel, it differs considerably from annealing in that the process lends itself to close control of the physical properties and in most cases does not soften the steel to the extent that

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annealing would. The final structure obtained from tempering a fully hardened steel is called tempered martensite. 虽然这过程使钢软化，但它与退火是大不相同的，因为回火适合于严格控制物理性能并在大多数情况下不会把钢软化到退火那种程度。回火完全淬硬钢得到的最终组织结构被称为回火马氏体。

Tempering is possible because of the instability of the martensite, the principal constituent of hardened steel. Low-temperature draws, from 300℉ to 400℉ (150℃~205℃), do not cause much decrease in hardness and are used principally to relieve internal strains. 由于马氏体这一淬硬钢主要成分的不稳定性，使得回火成为可能。低温回火， 300℉到400℉(150℃~205℃)，不会引起硬度下降很多，主要用于减少内部应变。

As the tempering temperatures are increased, the breakdown of the martensite takes place at a faster rate, and at about 600℉(315℃) the change to a structure called tempered martensite is very rapid. The tempering operation may be described as one of precipitation and agglomeration or coalescence of cementite. 随着回火温度的提高，马氏体以较快的速率分解，并在大约600℉(315℃)迅速转变为被称为回火马氏体的结构。回火作业可以描述为渗碳体析出和凝聚或聚结的过程。

A substantial precipitation of cementite begins at 600℉(315℃), which

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produces a decrease in hardness. Increasing the temperature causes coalescence of the carbides with continued decrease in hardness. 渗碳体的大量析出开始于600℉(315℃)，这使硬度下降。温度的上升会使碳化物聚结而硬度继续降低。

In the process of tempering, some consideration should be given to time as well as to temperature. Although most of the softening action occurs in the first few minutes after the temperature is reached, there is some additional reduction in hardness if the temperature is maintained for a prolonged time. 在回火过程中，不但要考虑温度而且要考虑时间。虽然大多数软化作用发生在达到所需温度后的最初几分钟，但如果此温度维持一段延长时间，仍会有些额外的硬度下降。

Usual practice is to heat the steel to the desired temperature and hold it there only long enough to have it uniformly heated. 通常的做法是将钢加热到所需温度并且仅保温到正好使其均匀受热。

Two special processes using interrupted quenching are a form of tempering. In both, the hardened steel is quenched in a salt bath held at a selected lower temperature before being allowed to cool. These processes, known as austempering and martempering, result in products having certain desirable physical properties.

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两种采用中断淬火的特殊工艺也是回火的形式。这两种工艺中，淬硬钢在其被允许冷却前先在一选定的较低温度盐浴淬火。这两种分别被称为奥氏体回火和马氏体回火的工艺，能使产品具有特定所需的物理性能。

Annealing 退火

The primary purpose of annealing is to soften hard steel so that it may be machined or cold worked. 退火的主要目的是使坚硬的钢软化以便机加工或冷作。

This is usually accomplished by heating the steel too slightly above the critical temperature, holding it there until the temperature of the piece is uniform throughout, and then cooling at a slowly controlled rate so that the temperature of the surface and that of the center of the piece are approximately the same. 通常是非常缓慢地将钢加热到临界温度以上，并将其在此温度下保持到工件全部均匀受热，然后以受控的速率慢慢地冷却，这样使得工件表面和内部的温度近似相同。

This process is known as full annealing because it wipes out all trace of previous structure, refines the crystalline structure, and softens the metal. Annealing also relieves internal stresses previously set up in the metal. 这过程被称为完全退火，因为它去除了以前组织结构的所有痕迹、细化晶粒并

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软化金属。退火也释放了先前在金属中的内应力。

The temperature to which a given steel should be heated in annealing depends on its composition; for carbon steels it can be obtained readily from the partial iron-iron carbide equilibrium diagram. When the annealing temperature has been reached, the steel should be held there until it is uniform throughout. 给定的钢其退火温度取决于它的成分;对碳钢而言可容易地从局部的铁碳合金平衡图得到。达到退火温度后，钢应当保持在此温度等到全部均匀受热。

This usually takes about 45min for each inch(25mm) of thickness of the largest section. For maximum softness and ductility the cooling rate should be very slow, such as allowing the parts to cool down with the furnace. The higher the carbon content, the slower this rate must be. 加热时间一般以工件的最大截面厚度计每英寸(25mm )大约需45min。为了得到最大柔软性和延展性冷却速率应该很慢，比如让零件与炉子一起冷下来。含碳量越高，冷却的速率必须越慢。

The heating rate should be consistent with the size and uniformity of sections, so that the entire part is brought up to temperature as uniformly as possible. 加热的速率也应与截面的尺寸及均匀程度相协调，这样才能使整个零件尽可能均匀地加热。

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Normalizing and Spheroidizing 正火和球化

The process of normalizing consists of heating the steel about 50℉ to 100℉ (10℃~40℃) above the upper critical range and cooling in still air to room temperature. 正火处理包括先将钢加热到高于上临界区50℉到100℉(10℃~40℃)然后在静止的空气中冷却到室温。

This process is principally used with low- and medium-carbon steels as well as alloy steels to make the grain structure more uniform, to relieve internal stresses, or to achieve desired results in physical properties. Most commercial steels are normalized after being rolled or cast. 退火主要用于低碳钢、中碳钢及合金钢，使晶粒结构更均匀、释放内应力或获得所需的物理特性。大多数商业钢材在轧制或铸造后都要退火。

Spheroidizing is the process of producing a structure in which the cementite is in a spheroidal distribution. If steel is heated slowly to a temperature just below the critical range and held there for a prolonged period of time, this structure will be obtained. 球化是使渗碳体产生成类似球状分布结构的工艺。如果把钢缓慢加热到恰好低于临界温度并且保持较长一段时间，就能得到这种组织结构。

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The globular structure obtained gives improved machinability to the steel. This treatment is particularly useful for hypereutectoid steels that must be machined. 所获得的球状结构改善了钢的可切削性。此处理方法对必须机加工的过共析钢特别有用。

Surface Hardening 表面硬化 Carburizing The oldest known method of producing a hard surface on steel is case hardening or carburizing. Iron at temperatures close to and above its critical temperature has an affinity for carbon. 渗碳

最早的硬化钢表面的方法是表面淬火或渗碳。铁在靠近并高于其临界温度时对碳具有亲合力。

The carbon is absorbed into the metal to form a solid solution with iron and converts the outer surface into high-carbon steel. The carbon is gradually diffused to the interior of the part. The depth of the case depends on the time and temperature of the treatment. 碳被吸收进金属与铁形成固溶体使外表面转变成高碳钢。碳逐渐扩散到零件内

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部。渗碳层的深度取决于热处理的时间和温度。

Pack carburizing consists of placing the parts to be treated in a closed container with some carbonaceous material such as charcoal or coke. It is a long process and used to produce fairly thick cases of from 0.03 to 0.16 in.(0.76~4.06mm) in depth. 固体渗碳的方法是将要处理的零件与木炭或焦炭这些含碳的材料一起放入密闭容器。这是一个较长的过程，用于产生深度为0.03到0.16 英寸(0.76~4.06mm)这么厚的硬化层。

Steel for carburizing is usually a low-carbon steel of about 0.15% carbon that would not in itself responds appreciably to heat treatment. In the course of the process the outer layer is converted into high-carbon steel with a content ranging from 0.9% to 1.2% carbon. 用于渗碳的一般是含碳量约为0.15%、本身不太适合热处理的低碳钢。在处理过程中外层转化为含碳量从0.9%到1.2%的高碳钢。

A steel with varying carbon content and, consequently, different critical temperatures requires a special heat treatment. 含碳量变化的钢具有不同的临界温度，因此需要特殊的热处理。

Because there is some grain growth in the steel during the prolonged carburizing treatment, the work should be heated to the critical temperature of the core and then cooled, thus refining the core structure. The steel

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should then be reheated to a point above the transformation range of the case and quenched to produce a hard, fine structure. 由于在较长的渗碳过程中钢内部会有些晶粒生长，所以工件应该加热到核心部分的临界温度再冷却以细化核心部分的组织结构。然后重新加热到高于外层转变温度再淬火以生成坚硬、细致的组织结构。

The lower heat-treating temperature of the case results from the fact that hypereutectoid steels are normally austenitized for hardening just above the lower critical point. A third tempering treatment may be used to reduce strains. 由于恰好高于低临界温度通常使过共析钢奥氏体化而硬化，所以对外层采用较低的热处理温度。第三次回火处理可用于减少应变。

Carbonitriding Carbonitriding, sometimes known as dry cyaniding or nicarbing, is a case-hardening process in which the steel is held at a temperature above the critical range in a gaseous atmosphere from which it absorbs carbon and nitrogen. 碳氮共渗

碳氮共渗，有时也称为干法氰化或渗碳氮化，是一种表面硬化工艺。通过把钢放在高于临界温度的气体中，让它吸收碳和氮。

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Any carbon-rich gas with ammonia can be used. The wear-resistant case produced ranges from 0.003 to 0.030 inch(0.08~ 0.76mm) in thickness. An advantage of carbonitriding is that the hardenability of the case is significantly increased when nitrogen is added, permitting the use of low-cost steels. 可以使用任何富碳气体加氨气，能生成厚度从0.003到0.030英寸(0.08~ 0.76mm)的耐磨外层。碳氮共渗的优点之一是加入氮后外层的淬透性极大增加，为使用低价钢提供条件。

Cyaniding Cyaniding, or liquid carbonitriding as it is sometimes called, is also a process that combines the absorption of carbon and nitrogen to obtain surface hardness in low-carbon steels that do not respond to ordinary heat treatment. 氰化

氰化，有时称为液体碳氮共渗，也是一种结合了吸收碳和氮来获得表面硬度的工艺，它主要用于不适合通常热处理的低碳钢。

The part to be case hardened is immersed in a bath of fused sodium cyanide salts at a temperature slightly above the Ac1 range, the duration of soaking depending on the depth of the case. The part is then quenched in water or oil to obtain a hard surface.

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需表面硬化的零件浸没在略高于Ac1温度熔化的氰化钠盐溶液中，浸泡的持续时间取决于硬化层的深度。然后将零件在水或油中淬火。

Case depths of 0.005 to 0.015in. (0.13~0.38mm) may be readily obtained by this process. Cyaniding is used principally for the treatment of small parts. 通过这样处理可以容易地获得0.005到0.015英寸(0.13~0.38mm)的硬化深度。氰化主要用于处理小零件。

Nitriding Nitriding is somewhat similar to ordinary case hardening, but it uses a different material and treatment to create the hard surface constituents. 渗氮

渗氮有些类似普通表面硬化，但它采用不同的材料和处理方法来产生坚硬表面成分。

In this process the metal is heated to a temperature of around 950℉(510℃) and held there for a period of time in contact with ammonia gas. Nitrogen from the gas is introduced into the steel, forming very hard nitrides that are finely dispersed through the surface metal. 这种工艺中金属加热到约950℉(510℃)，然后与氨气接触一段时间。氨气中的氮进入钢内，形成细微分布于金属表面又十分坚固的氮化物。

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Nitrogen has greater hardening ability with certain elements than with others, hence, special nitriding alloy steels have been developed. 氮与某些元素的硬化能力比其它元素大，因此开发了专用的渗氮合金钢。 Aluminum in the range of 1% to 1.5% has proved to be especially suitable in steel, in that it combines with the gas to form a very stable and hard constituent. The temperature of heating ranges from 925℉ to 1,050℉(495℃~565℃).

在钢中含铝1%到1.5%被证明特别合适，它能与氨气结合形成很稳定坚固的成分。其加热温度范围为925℉到1,050℉ (495℃~565℃)。

Liquid nitriding utilizes molten cyanide salts and, as in gas nitriding, the temperature is held below the transformation range. Liquid nitriding adds more nitrogen and less carbon than either cyaniding or carburizing in cyanide baths. 液体渗氮利用熔化的氰化物盐，就像气体渗氮，温度保持在低于转化范围内。液体渗氮时在氰化物溶液中加入比氰化及渗碳都较多的氮和较少的碳。

Case thickness of 0.001 to 0.012in.(0.03~0.30mm) is obtained, whereas for gas nitriding the case may be as thick as 0.025 in.(0.64mm). In general the uses of the two-nitriding processes are similar. 液体渗氮可以获得厚度为0.001到0.012英寸 (0.03~0.30mm)的硬化层，然而气体渗氮则能获得厚0.025英寸(0.64mm)的硬化层。一般而言两种渗氮方法的用途是类

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似的。

Nitriding develops extreme hardness in the surface of steel. This hardness ranges from 900 to 1,100 Brinell, which is considerably higher than that obtained by ordinary case hardening. 渗氮在钢表面获得远远超出正常标准的硬度。其硬度范围为900到1,100布氏硬度，这远高于普通表面硬化所获得的硬度。

Nitriding steels, by virtue of their alloying content, are stronger than ordinary steels and respond readily to heat treatment. It is recommended that these steels be machined and heat-treated before nitriding, because there is no scale or further work necessary after this process. 由于渗氮钢的合金比例，它们比普通钢更强，也容易热处理。建议对这种钢在渗氮前先机加工和热处理，因为渗氮后没有剥落并不需要更多的加工。

Fortunately, the interior structure and properties are not affected appreciably by the nitriding treatment and, because no quenching is necessary, there is little tendency to warp, develop cracks, or change condition in any way. The surface effectively resists corrosive action of water, saltwater spray, alkalies, crude oil, and natural gas. 值得庆幸的是由于渗氮处理一点都不影响内部结构和性能，也无需淬火，所以几乎没有任何产生翘曲、裂缝及变化条件的趋势。这种表面能有效地抵御水、盐雾、碱、原油和天然气的腐蚀反应。

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Casting is a manufacturing process in which molten metal is poured or injected and allowed to solidify in a suitably shaped mold cavity. During or after cooling, the cast part is removed from the mold and then processed for delivery. 铸造是一种将熔化的金属倒入或注入合适的铸模腔并且在其中固化的制造工艺。在冷却期间或冷却后，把铸件从铸模中取出，然后进行交付。

Casting processes and cast-material technologies vary from simple to highly complex. Material and process selection depends on the part’s complexity and function, the product’s quality specifications, and the projected cost level. 铸造工艺和铸造材料技术从简单到高度复杂变化很大。材料和工艺的选择取决于零件的复杂性和功能、产品的质量要求以及成本预算水平。

Castings are parts that are made close to their final dimensions by a casting process. With a history dating back 6,000 years, the various casting processes are in a state of continuous refinement and evolution as technological advances are being made. 通过铸造加工，铸件可以做成很接近它们的最终尺寸。回溯6,000年历史，各种各样的铸造工艺就如同科技进步一样处于一个不断改进和发展的状态。

Sand Casting 砂型铸造

Sand casting is used to make large parts (typically iron, but also bronze,

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brass, aluminum). Molten metal is poured into a mold cavity formed out of sand (natural or synthetic). 砂型铸造用于制造大型零件(具有代表性是铁，除此之外还有青铜、黄铜和铝)。将熔化的金属倒入由型砂(天然的或人造的)做成铸模腔。

The processes of sand casting are discussed in this section, including patterns, sprues and runners, design considerations, and casting allowance. 本节讨论砂型铸造工艺，包括型模、浇注口、浇道、设计考虑因素及铸造余量。 The cavity in the sand is formed by using a pattern (an approximate duplicate of the real part), which are typically made out of wood, sometimes metal. The cavity is contained in an aggregate housed in a box called the flask. 砂型里的型腔是采用型模(真实零件的近似复制品)构成的，型模一般为木制，有时也用金属制造。型腔整个包含在一个被放入称为砂箱的箱子里的组合体内。

Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages. Cores are placed in the cavity to form holes of the desired shapes. Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold. 砂芯是插入铸模的砂型，用于生成诸如孔或内通道之类的内部特征。砂芯安放在型腔里形成所需形状的孔洞。砂芯座是加在型模、砂芯或铸模上的特定区域，用

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来在铸模内部定位和支撑砂芯。

A riser is an extra void created in the mold to contain excessive molten material. The purpose of this is to feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting. 冒口是在铸模内部增加的额外空间，用于容纳过多的熔化金属。其目的是当熔化金属凝固和收缩时往型腔里补充熔化金属，从而防止在主铸件中产生孔隙。

In a two-part mold, which is typical of sand castings, the upper half, including the top half of the pattern, flask, and core is called cope and the lower half is called drag, as shown in Fig.3.1. The parting line or the parting surface is line or surface that separates the cope and drag. 在典型砂型铸造的两箱铸模中，上半部分(包括型模顶半部、砂箱和砂芯)称为上型箱，下半部分称为下型箱，见图3.1所示。分型线或分型面是分离上下型箱的线或面。

The drag is first filled partially with sand, and the core print, the cores, and the gating system are placed near the parting line. The cope is then assembled to the drag, and the sand is poured on the cope half, covering the pattern, core and the gating system. 首先往下型箱里部分地填入型砂和砂芯座、砂芯，并在靠近分型线处放置浇注系统。然后将上型箱与下型箱装配在一起，再把型砂倒入上型箱盖住型模、砂芯和

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浇注系统。

The sand is compacted by vibration and mechanical means. Next, the cope is removed from the drag, and the pattern is carefully removed. The object is to remove the pattern without breaking the mold cavity. 型砂通过振动和机械方法压实。然后从下型箱上撤掉上型箱，小心翼翼地取出型模。其目的是取出型模而不破坏型腔。

This is facilitated by designing a draft, a slight angular offset from the vertical to the vertical surfaces of the pattern. This is usually a minimum of 1.5mm(0.060in.), whichever is greater. The rougher the surface of the pattern, the more the draft to be provided. 通过设计拔模斜度—型模垂直相交表面的微小角度偏移量—来使取出型模变得容易。拔模斜度最小一般为1.5mm(0.060in.)，只能比此大。型模表面越粗糙，则拔模斜度应越大。

The molten material is poured into the pouring cup, which is part of the gating system that supplies the molten material to the mold cavity. 熔化的金属从浇注杯注入型腔，浇注杯是浇注系统向型腔提供熔化金属的部分。 The vertical part of the gating system connected to the pouring cup is the sprue, and the horizontal portion is called the runners and finally to the multiple points where it is introduced to the mold cavity called the gates.

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将浇注系统的垂直部分与浇注杯连接的是浇注口，浇注系统的水平部分称为浇道，最后到多点把熔化金属导入型腔的称为闸道。

Additionally there are extensions to the gating system called vents that provide the path for the built-up gases and the displaced air to vent to the atmosphere. 除此之外，还有称为排放口的浇注系统延长段，它为合成气体和置换空气排放到大气提供通道。

The cavity is usually made oversize to allow for the metal contraction as it cools down to room temperature. This is achieved by making the pattern oversize. To account for shrinking, the pattern must be made oversize by these factors on the average. These are linear factors and apply in each direction. 型腔通常大于所需尺寸以允许在金属冷却到室温时收缩。这通过把型模做得大于所需尺寸来达到。为解决收缩效应，一般而言型模做得比所需尺寸大，必须考虑线性因素并作用于各个方向。

These shrinkage allowances are only approximate, because the exact allowance is determined by the shape and size of the casting. In addition, different parts of the casting might require different shrinkage allowances. 收缩余量仅仅是近似的，因为准确的余量是由铸件的形状和尺寸决定的。另外，铸件的不同部分也可能需要不同的收缩余量。

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Sand castings generally have a rough surface sometimes with surface impurities, and surface variations. A machining (finish) allowance is made for this type of defect. 砂型铸件一般表面粗糙，有时还带有表面杂质和表面变异。对这类缺陷采用机加工(最后一道工序)的余量。

In general, typical stages of sand casting operation include (as shown in Fig.3.2): 1. Patterns are made. These will be the shape used to form the cavity in the sand. 一般而言，砂型铸造作业的典型阶段包括(如图3.2所示)： 1. 制作型模。做成用于在型砂中形成型腔的形状。

2. Cores may also be made at this time. These cores are made of bonded sand that will be broken out of the cast part after it is complete. 3. Sand is mulled (mixed) thoroughly with additives such as bentonite to increase bonding and overall strength. 2. 同时还要制作砂芯。这些砂芯用粘结砂做成，等铸件完成后将被打碎取出。 3. 型砂与膨润土之类的添加剂充分地混合以增强连接及整体强度。

4. Sand is formed about the patterns, and gates, runners, risers, vents

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and pouring cups are added as needed. A compaction stage is typically used to ensure good coverage and solid molds. 4. 型砂在型模周围成形，并根据需要安放闸道、浇道、冒口、排放口和浇注杯等。通常要采取压紧步骤来保证良好的覆盖和坚固的铸型。

Cores may also be added to make concave or internal features for the cast part. Alignment pins may also be used for mating the molds later. Chills may be added to cool large masses faster. 安放砂芯来制成铸件的凹形结构或内部特征。为了以后铸模匹配还要用到定位销。对大质量铸件可能需要加入冷却物来使其较快冷却。

5. The patterns are removed, and the molds may be put through a baking stage to increase strength. 6. Mold halves are mated and prepared for pouring metal. 5. 取走型模，将铸模烘焙以增加强度。 6. 匹配上下铸模，做好浇铸金属的准备。

7. Metal is preheated in a furnace or crucible until is above the liquidus temperature in a suitable range (we don’t want the metal solidifying before the pour is complete). The exact temperature may be closely controlled depending upon the application. 7. 金属在熔炉或坩埚中预热到高于液化温度的一个合适范围内(不希望金属在

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浇铸完成前凝固)。确切的温度要根据应用场合严格控制。

Degassing, and other treatment processes may be done at this time, such as removal of impurities (i.e. slag). Some portion of this metal may be remelted scrap from previously cast parts—10% is reasonable. 在此期间还要进行排气和其它处理步骤，例如去除杂质(即熔渣)。可以加入一定量原先是这种金属铸件的废料再融化—10%是适当的。

8. The metal is poured slowly, but continuously into the mold until the mold is full. 9. As the molten metal cools (minutes to days), the metal will shrink and the volume will decrease. During this time molten metal may backflow from the molten risers to feed the part and maintain the same shape. 8. 将金属缓慢而连续地注满型模。

9. 随着熔化金属的冷却(几分钟到几天)，金属收缩体积减小。在此期间熔化金属可能从冒口回流供给零件以保持其形状不变。

10. Once the part starts to solidify small dendrites of solid material form in the part. During this time metal properties are being determined, and internal stresses are being generated. If a part is allowed to cool slowly enough at a constant rate then the final part will be relatively homogenous and stress free.

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10. 在零件开始凝固其内部形成固态金属的小型树枝状结晶期间金属性能被确定，同时也产生了内应力。如果零件以恒定速率冷却得足够缓慢，最终零件将相对均质并释放内应力。

11. Once the part has completely solidified below the eutectic point it may be removed with no concern for final metal properties. At this point the sand is simply broken up, and the part removed. At this point the surface will have a quantity of sand adhering to the surface, and solid cores inside. 11. 一旦零件在共析点以下完全凝固，可以不考虑金属的最后性能而将其取出。这时可以简单地打碎砂型并取出零件，但零件表面会有大量型砂粘附着，内部还有实心的砂芯。

12. A bulk of the remaining sand and cores can be removed by mechanically striking the part. Other options are to use a vibrating table, sand/shot blaster, hand labor, etc. 12.大量的剩余型砂和砂芯要通过机械敲击零件来去除。其它的选择还有采用振动台、喷砂/喷丸机、手工作业等等。

13. The final part is cut off the runner gate system, and is near final shape using cutters, torches, etc. Grinding operations are used to remove any remaining bulk. 14. The part is taken down to final shape using machining operations. And cleaning operations may be used to remove oxides, etc.

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13. 最后零件要用刀具、喷枪等切掉浇道闸道系统，这样就接近最终形状了。再用磨削作业去除多余的部分。

14. 通过机加工将零件切削到最终形状。可能还要用清洗作业去除氧化物等。 Investment casting 熔模铸造

Investment casting is also known as the lost wax process. This process is one of the oldest manufacturing processes. The Egyptians used it in the time of the Pharaohs to make gold jewelry (hence the name Investment) some 5,000 years ago. 熔模铸造也称为失蜡加工。这是最古老的制造工艺之一。大约在5,000年前的法老王时代，埃及人就用它制造黄金饰品(因此而得名投资)。

Intricate shapes can be made with high accuracy. In addition, metals that are hard to machine or fabricate are good candidates for this process. It can be used to make parts that cannot be produced by normal manufacturing techniques, such as turbine blades that have complex shapes, or airplane parts that have to withstand high temperatures. 复杂的形状能被高精度地制造。另外较难机加工或制作的金属都能用此工艺。它还能用于生产一般制造技术无法生产的零件，例如有复杂形状的涡轮叶片或必须耐得住高温的飞机零件。

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The mold is made by making a pattern using wax or some other material that can be melted away. This wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin. This is dried and the process of dipping in the slurry and drying is repeated until a robust thickness is achieved. 制作铸型的型模采用石蜡或其它一些能被融化掉的材料做成。石蜡型模浸泡在耐热浆里，让它覆盖型模并形成外壳，然后使其变干。重复这个浸泡、变干的过程直至获得足够的厚度。

After this, the entire pattern is placed in an oven and the wax is melted away. This leads to a mold that can be filled with the molten metal. Because the mold is formed around a one-piece pattern (which does not have to be pulled out from the mold as in a traditional sand casting process), very intricate parts and undercuts can be made. 完成后把整个型模放在烤箱里融化石蜡。这样就做成了能填充熔化金属的铸型。由于这种铸型是环绕整块型模形成的(无需像传统的砂型铸造工艺那样拔模)，能制作十分复杂的零件和浮雕。

The wax pattern itself is made by duplicating using a stereo lithography or similar model—which has been fabricated using a computer solid model master. 石蜡型模本身能用立体制版或类似的模型复制—这可以采用计算机立体模型原

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版制作。

The materials used for the slurry are a mixture of plaster, a binder and powdered silica, a refractory, for low temperature melts. For higher temperature melts, sillimanite or alumina-silicate is used as a refractory, and silica is used as a binder. 对较低熔化温度而言，用于耐热浆的材料是石膏作粘合剂和用粉末状硅石作耐温材料的混合物。对较高熔化温度而言，则采用硅线石或氧化铝硅酸盐作耐温材料、无水硅酸作粘合剂。

Depending on the fineness of the finish desired additional coatings of sillimanite and ethyl silicate may be applied. The mold thus produced can be used directly for light castings, or be reinforced by placing it in a larger container and reinforcing it more slurry. 根据最后所需光洁度也可采用硅线石和乙烷基硅酸盐。这样生成的铸模可直接用于薄壁铸件或通过将其放在较大容器内用更多耐热浆加强。

Just before the pour, the mold is pre-heated to about 1,000℃(1,832℉) to remove any residues of wax, harden the binder. The pour in the pre-heated mold also ensures that the mold will fill completely. 在正要浇铸之前，将型模预热到约1,000℃(1,832℉)以去除剩余石蜡、硬化粘合剂。在预热的型模中浇铸也能保证型模完全充满。

Pouring can be done using gravity, pressure or vacuum conditions.

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第三篇：化学专业英语中英译

United 1 材料科学与工程

材料在我们的文化中比我们认识到的还要根深蒂固。如交通、房子、衣物，通讯、娱乐和食 物的生产，实际上，我们日常生活中的每一部分都或多或少地受到材料的影响。历史上社会 的发展、先进与那些能满足社会需要的材料的生产及操作能力密切相关。实际上，早期的文 明就以材料的发展程度来命名，如石器时代，铜器时代。 早期人们能得到的只有一些很有限的天然材料，如石头、木材、粘土等。渐渐地，他们通过 技术来生产优于自然材料的新材料，这些新材料包括陶器和金属。进一步地，人们发现材料 的性质可以通过加热或加入其他物质来改变。在这点上，材料的应用完全是一个选择的过程。 也就是说，在一系列非常有限的材料中，根据材料的优点选择一种最适合某种应用的材料。 直到最近，科学家才终于了解材料的结构要素与其特性之间的关系。这个大约是过去的 60 年中获得的认识使得材料的性质研究成为时髦。因此，成千上万的材料通过其特殊的性质得 以发展来满足我们现代及复杂的社会需要。 很多使我们生活舒适的技术的发展与适宜材料的获得密切相关。一种材料的先进程度通常是 一种技术进步的先兆。比如，没有便宜的钢制品或其他替代品就没有汽车。在现代，复杂的 电子器件取决于所谓的半导体零件.

材料科学与工程 有时把材料科学与工程细分成材料科学和材料工程学科是有用的。严格地说，材料科学涉及 材料到研究材料的结构和性质的关系。相反，材料工程是根据材料的结构和性质的关系来设 计或操纵材料的结构以求制造出一系列可预定的性质。从功能方面来说，材料科学家的作用 是发展或合成新的材料，而材料工程师是利用已有的材料创造新的产品或体系，和/或发展 材料加工新技术。多数材料专业的本科毕业生被同时训练成材料科学家和材料工程师。 “structure”一词是个模糊的术语值得解释。简单地说，材料的结构通常与其内在成分的排 列有关。原子内的结构包括介于单个原子间的电子和原子核的相互作用。在原子水平上，结 构包括原子或分子与其他相关的原子或分子的组织。在更大的结构领域上，其包括大的原子 团，这些原子团通常聚集在一起，称为“微观”结构，意思是可以使用某种显微镜直接观察 得到的结构。最后，结构单元可以通过肉眼看到的称为宏观结构。

“Property” 一词的概念值得详细阐述。在使用中，所有材料对外部的刺激都表现出某种反 应。比如，材料受到力作用会引起形变，或者抛光金属表面会反射光。材料的特征取决于其 对外部刺激的反应程度。通常，材料的性质与其形状及大小无关。 实际上，所有固体材料的重要性质可以概括分为六类：机械、电学、热学、磁学、光学和腐 蚀性。对于每一种性质，其都有一种对特定刺激引起反应的能力。如机械性能与施加压力引 起的形变有关，包括弹性和强度。对于电性能，如电导性和介电系数，特定的刺激物是电场。 固体的热学行为则可用热容和热导率来表示。磁学性质表示一种材料对施加的电场的感应能 力。对于光学性质，刺激物是电磁或光照。用折射和反射来表示光学性质。最后，腐蚀性质 表示材料的化学反应能力。 除了结构和性质，材料科学和工程还有其他两个重要的组成部分，即加工和性能。如果考虑 这四个要素的关系，材料的结构取决于其如何加工。另外，材料的性能是其性质的功能。因 此，材料的加工、结构、性质和功能的关系可以用以下线性关系来表示： 加工——结构——性质——性能。

为什么研究材料科学与工程? 为什么研究材料科学与工程?许多应用科学家或工程师，不管他们是机械的、民事的、化学 的或电子的领域的，都将在某个时候面临材料的设计问题。如用具的运输、建筑的超级结构、 油的精炼成分、或集成电路芯片。当然，材料科学家和工程师是从事材料研究和设计的专家。

很多时候，材料的问题就是从上千个材料中选择出一个合适的材料。对材料的最终选择有几 个原则。首先，现场工作条件必须进行表征。只有在少数情况下材料在具有最优或理想的综 合性质。因此，有必要对材料的性质进行平衡。典型的例子是当考虑材料的强度和延展性时， 而通常材料具有高强度但却具有低的延展性。这时对这两种性质进行折中考虑很有必要。 其次，选择的原则是要考虑材料的性质在使用中的磨损问题。如材料的机械性能在高温或腐 蚀环境中会下降。 最后，也许是最重要的原则是经济问题。最终产品的成本是多少?一种材料的可以有多种理 想的优越性质，但不能太昂贵。这里对材料的价格进行折中选择也是可以的。产品的成本还 包括组装中的费用。 工程师与科学家越熟悉材料的各种性质、结构、功能之间的关系以及材料的加工技术，根据 以上的几个原则，他或她对材料的明智选择将越来越熟练和精确。

Unit 2 Classification of Materials

Solid materials have been conveniently grouped into three basic classifications: metals, ceramics, and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates. In addition, there are three other groups of important engineering materials—composites, semiconductors, and biomaterials.

译文：固体材料被便利的分为三个基本的类型：金属，陶瓷和聚合物。这个分类是首先基于化学组成和原子结构来分的，大多数材料落在明显的一个类别里面，尽管有许多中间品。除此之外， 有三类其他重要的工程材料-复合材料，半导体材料和生物材料。

Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics; biomaterials are implanted into the human body. A brief explanation of the material types and representative characteristics is offered next.

译文：复合材料由两种或者两种以上不同的材料组成，然而半导体由于它们非同寻常的电学性质而得到使用;生物材料被移植进入人类的身体中。关于材料类型和他们特殊的特征的一个简单的解释将在后面给出。 METALS

Metallic materials are normally combinations of metallic elements. They have large numbers of nonlocalized electrons; that is, these electrons are not bound to particular atoms. Many properties of metals are directly able to these electrons. be bound to 被约束于。be attribute to 归属于。。归因于。。

译文：金属材料通常由金属元素组成。它们有大量无规则运动的电子。也就是说，这些电子不是被约束于某个特定的原子。金属的许多性质直接归属这些不规则运动的电子。

Metals are extremely good conductors of electricity and heat and are not transparent to visible light; a polished metal surface has a lustrous appearance. Furthermore, metals are quite strong, yet deformable, which accounts for their extensive use in structural applications. 科技英语在讲述科学真理的时候通常用主动语态。如： Metals are extremely good conductors of electricity Deformable ?

译文：金属是十分好的电和热的导体，它们对可见光不透明;一个抛光的金属表面有光辉的外表。除此之外，金属是十分硬的，也是可变 形的，这个性质解释了它们广泛使用在结构方面的应用。 CERAMICS Ceramics are compounds between metallic and nonmetallic elements; they are most frequently oxides, nitrides, and carbides. The wide range of materials that falls within this classification includes ceramics that are composed of clay minerals, cement, and glass. that引导的定语从句

译文：陶瓷是介于金属和非金属元素之间的化合物;它们通常是氧化物，氮化物和碳化物。落在这个分类种类中的宽的材料范围包括陶瓷，它们由粘土矿物，水泥和玻璃组成。

These materials are typically insulative to the passage of electricity and heat, and are more resistant to high temperatures and harsh environments than metals and polymers. With regard to mechanical behavior, ceramics are hard but very brittle. more„. Than„.. with regard to„. 译文：这些材料是典型的电和热的绝缘体，并且它们比金属和聚合物更加耐高温和耐苛刻的环境。至于机械性能，陶瓷是硬的但是却很脆。

POLYMERS Polymers include the familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements; furthermore, they have very large molecular structures. These materials typically have low densities and may be extremely flexible. 译文：聚合物包括常见的塑料和橡胶材料。它们中的大多数是有机化合物，这些化合物是以化学的方法把碳、氢和其他非金属元素组合而成。因此，它们有非常大的分子结构。这些材料通常有低的密度并且可能十分柔软。 COMPOSITES A number of composite materials have been engineered that consist of more than one material type. Fiberglass is a familiar example, in which glass fibers are embedded within a polymeric material. more than„

译文：许多复合材料被作用工程使用，它们由至少一种类型的材料组成。玻璃丝是一个熟悉的例子，玻璃纤维被埋入聚合物材料中。

A composite is designed to display a combination of the best characteristics of each of the component materials. Fiberglass acquires strength from the glass and flexibility from the polymer. Many of the recent material developments have involved composite materials. 译文：为了联合显示每一种组分材料最好的特性，一种复合材料被设计出来。玻璃丝从玻璃中获得强度并且从聚合物中获得柔软性。最近发展中的绝大多数材料包含了复合材料。 SEMICONDUCTORS

Semiconductors have electrical properties that are intermediate between the electrical conductors and insulators. Furthermore, the electrical characteristics of these materials are extremely sensitive to the presence of minute concentrations of impurity atoms, which concentrations may be controlled over very small spatial regions. be sensitive to 对„敏感的

译文：半导体有电的性质，它们是介于电导体和绝缘体之间的中间物。除此之外，这些材料的电学性质对微量杂质原子的存在十分敏感，杂质原子浓度可能只是在一个十分小的区域内可以控制。 The semiconductors have made possible the advent of integrated circuitry that has totally revolutionized the electronics and computer industries (not to mention our lives) over the past two decades. 译文：这些半导体使得集成电路的出现变得可能，在过去20多年间，这些集成电路革新了电子装置和计算机工业(更不用说我们的生活)。

BIOMATERIALS Biomaterials are employed in components implanted into the human body for replacement of diseased or damaged body parts. These materials must not produce toxic substances and must be compatible with body tissues (i.e., must not cause adverse biological reactions). 译文：生物材料被应用于移植进入人类身体以取代病变的或者损坏的身体部件。这些材料不能产生有毒物质而且必须同人身体器官要相容(比如，不能导致相反的生物反应)。

All of the above materials—metals, ceramics, polymers, composites, and semiconductors—may be used as biomaterials. For example, some of the biomaterials such as CF/C (carbon fibers/carbon) and CF/PS (polysulfone) are utilized in artificial hip replacements. 译文：所有以上材料-金属，陶瓷，聚合物，复合材料和半导体材料可能用作生物材料。比如，如CF/C和CF/PS(聚砜)这些生物材料被用作人工肾的取代物。

ADVANCED MATERIALS Materials that are utilized in high-technology (or high-tech) applications are sometimes termed advanced materials. By high technology we mean a device or product that operates or functions using relatively intricate and sophisticated principles; examples include electronic equipment (VCRs, CD players, etc.), computers, fiberoptic systems, spacecraft, aircraft, and military rocketry. 译文：用在高科技中的材料有时被称作先进材料。借助于高科技，我们预定一个装置或者产品，这些产品用相对复杂和熟练的原理运转或者起作用;这些例子包括电子设备( VCRs, CD 播放器)，计算机，光纤系统，宇宙飞船，航天飞机和军事火箭。

These advanced materials are typically either traditional materials whose properties have been enhanced or newly developed, high-performance materials. Furthermore, they may be of all material types (e.g., metals, ceramics, polymers), and are normally relatively expensive. 译文：这些高级材料或是典型的传统材料，它们的性质被提高，最近开发出来的，高性能材料。除此之外，它们可能是所有材料类型(比如，金属、陶瓷和聚合物)，通常相对较贵。

In subsequent chapters are discussed the properties and applications of a number of advanced materials—for example, materials that are used for lasers, integrated circuits, magnetic information storage, liquid crystal displays (LCDs), fiber optics, and the thermal protection system for the Space Shuttle Orbiter. 译文： 在下面的章节将讨论众多先进材料的性质和应用-比如被用作激光，集成电路，磁信息存储，液晶显示器，光纤和空间舱轨道的热保护系统的材料。

MODERN MATERIALS’ NEEDS

In spite of the tremendous progress that has been made in the discipline of materials science and engineering within the past few years, there still remain technological challenges, including the development of even more sophisticated and specialized materials, as well as consideration of the

environmental impact of materials production. Some comment is appropriate relative to these issues so as to round out this perspective. 译文：在过去几年内，不论材料科学与工程的规律取得了巨大的进步，仍然有一些技术挑战，包括开发更加熟练的专业化的材料，并且考虑材料生产对环境导致的影响。针对这个问题，一些评论是十分相关的。

Nuclear energy holds some promise, but the solutions to the many problems that remain will necessarily involve materials, from fuels to containment structures to facilities for the disposal of radioactive waste.

译文：核能还保持着一些承诺，但是解决许多仍然存在的问题，将有必要把材料包括在里，从燃料到保护结构以便方便处置这些放射性废料。

Significant quantities of energy are involved in transportation. Reducing the weight of transportation vehicles (automobiles, aircraft, trains, etc.), as well as increasing engine operating temperatures, will enhance fuel efficiency. New high strength,low-density structural materials remain to be developed, as well as materials that have higher-temperature capabilities, for use in engine components. 译文：相当数量的能源用在交通上。减少交通工具(汽车，飞机，火车等)的重量，和提高引擎操作温度，将提高燃料的使用效率。新的 高强，低密度结构材料仍在发展，用作引擎部位能耐高温材料也在发展中。

Furthermore, there is a recognized need to find new,

economical sources of energy, and to use the present resources more efficiently. Materials will undoubtedly play a significant role in these developments. 译文：除此之外，寻找新的、经济的能源资源，并且更加有效的使用目前现存的资源是公认为必须的。材料将毫无疑问的在这些发展过程中扮演重要的角色。

For example, the direct conversion of solar into electrical energy has been demonstrated. Solar cells employ some rather complex and expensive materials. To ensure a viable technology, materials that are highly efficient in this conversion process yet less costly must be developed. 译文：比如，太阳能直接转化为电能已经被证实了。太阳能电池使用相当复杂并且昂贵的材料。为了保证技术的可行，在这个转化过程中的高效但不贵的材料必须被发展。

Furthermore, environmental quality depends on our ability to control air and water pollution. Pollution control techniques employ various materials. In addition, materials processing and refinement methods need to be improved so that they produce less environmental degradation, that is, less pollution and less despoilage of the landscape from the mining of raw materials. 译文：除此之外，环境质量取决于我们控制大气和水污染的能力。污染控制技术使用了各种材料。再者，材料加工和精制的方法需要改善以便它们产生很少的环境退化，也就是说，在生材料加工过程中，带来更少的污染和更少的对自然环境的破坏。

Also, in some materials manufacturing processes, toxic substances are produced, and the ecological impact of their disposal must be considered. Many materials that we use are derived from resources that are nonrenewable, that is, not capable of being regenerated. These include polymers, for which the prime raw material is oil, and some metals. These nonrenewable resources are gradually becoming depleted. 译文：也，在一些材料生产过程中，有毒物质产生了，并且它们的处置对生态产生的影响必须加以考虑。我们使用的许多材料来源于不可再生的资源，不可再生也就是说不能再次生成的。这些材料包括聚合物，最初的原生材料是油和一些金属。这些不可再生的资源逐渐变得枯竭

which necessitates: 1) the discovery of additional reserves, 2) the development of new materials having comparable properties with less adverse environmental impact, and/or 3) increased recycling efforts and the development of new recycling technologies. 译文：下面是必须的：1)发现另外的储藏，2)开发拥有较少负环境影响的新材料，3)增加循环的努力并且开发新的循环技术。 As a consequence of the economics of not only production but also environmental impact and ecological factors, it is becoming increasingly important to consider the ‘‘cradle-to-grave’’ life cycle of materials relative to the overall manufacturing process.

译文：结果，不仅是生产，而且环境影响和生态因子，和材料整个生产过程紧密相关的材料“一生”的生命周期的考虑变得越来越重要。

第四篇：英语专业中英文简历模版

个人简历

姓名：性别：

出生日期：

就读院校：

联系方式：手机：

电子邮箱：

地址：

自我定位：爱岗敬业，乐于奉献;工作认真投入，执行力强;生活中兴趣广泛，善于交际。

大学期间参加活动

所受奖励

个人奖项：

集体奖项：

外语水平

校内主修课程包括高级英语，英汉翻译，汉英翻译，高级口译，公共演讲，英语国家文化，语言学，二外西班牙语等;

选修课程包括西方经济学基础，外贸函电，美学，中外民俗等;

已获得大学英语等级考试六级(CET-6);英语专业等级考试四级(TEM-4);托业考试(TOEIC)905分;职业英语等级二级。

其他技能

获得天津市普通话资格证(二级甲等);

熟练运用Office办公软件，视频和电子杂志制作软件。

机动车驾驶证C1牌照。

Resume

Name:Gender:

Birth:

Education:

Connect me: Mobile:

E-mail:

Address:

Activities Participated during University

Honors

 Individual Awards:

 Collective Awards: Language skills

Required courses: Advanced English, English-Chinese Translation, Chinese-English Translation，

Interpretation, Public Speech, Linguistics, and Spanish

Elective courses: Western Economics, Business Correspondence, Esthetics, Chinese and Foreign

Customs

Received CET-6 and TEM-4 certification, TOEIC(Score:905)

Other skills

Received Mandarin certification (2A)

Microsoft Office application

Good command of video and E-magazine software

Drive license(C1)

第五篇：专业英语(中英论文翻译用)

沈阳建筑工程学院毕业设计(论文) 42

土建高层结构与钢结构(中英文翻译)

近年来，尽管一般的建筑结构设计取得了很大的进步，但是取得显著成绩的还要属超高层建筑结构设计。

最初的高层建筑设计是从钢结构的设计开始的。钢筋混凝土和受力外包钢筒系统运用起来是比较经济的系统，被有效地运用于大批的民用建筑和商业建筑中。50层到100层的建筑被定义为超高层建筑。而这种建筑在美国得广泛的应用是由于新的结构系统的发展和创新。

这样的高度需要增大柱和梁的尺寸，这样以来可以使建筑物更加坚固以至于在允许的限度范围内承受风荷载而不产生弯曲和倾斜。过分的倾斜会导致建筑的隔离构件、顶棚以及其他建筑细部产生循环破坏。除此之外，过大的摇动也会使建筑的使用者们因感觉到这样的的晃动而产生不舒服的感觉。无论是钢筋混凝土结构系统还是钢结构系统都充分利用了整个建筑的刚度潜力，因此不能指望利用多余的刚度来限制侧向位移。

在钢结构系统设计中，经济预算是根据每平方英寸地板面积上的钢材的数量确定的。图示1中的曲线A显示了常规框架的平均单位的重量随着楼层数的增加而增加的情况。而曲线B显示则显示的是在框架被保护而不受任何侧向荷载的情况下的钢材的平均重量。上界和下界之间的区域显示的是传统梁柱框架的造价随高度而变化的情况。而结构工程师改进结构系统的目的就是减少这部分造价。

钢结构中的体系：钢结构的高层建筑的发展是几种结构体系创新的结果。这些创新的结构已经被广泛地应用于办公大楼和公寓建筑中。

刚性带式桁架的框架结构：为了联系框架结构的外柱和内部带式桁架，可以在建筑物的中间和顶部设置刚性带式桁架。1974年在米望基建造的威斯康森银行大楼就是一个很好的例子。

框架筒结构： 如果所有的构件都用某种方式互相联系在一起，整个建筑就像是从地面发射出的一个空心筒体或是一个刚性盒子一样。这个时候此高层建筑的整个结构抵抗风荷载的所有强度和刚度将达到最大的效率。这种特殊的结构体系首次被芝加哥的43层钢筋混凝土的德威特红棕色的公寓大楼所采用。但是这种结构体系的的所有应用中最引人注目的还要属在纽约建造的100层的双筒结构的世界贸易中心大厦。

斜撑桁架筒体： 建筑物的外柱可以彼此独立的间隔布置，也可以借助于通过梁柱中心线的交叉的斜撑构件联系在一起，形成一个共同工作的筒体结构。这种高度的结构体系首次被芝加哥的John Hancock 中心大厦采用。这项工程所耗用的刚才量与传统的四十层

沈阳建筑工程学院毕业设计(论文) 43 高楼的用钢量相当。

筒体： 随着对更高层建筑的要求不断地增大。筒体结构和斜撑桁架筒体被设计成捆束状以形成更大的筒体来保持建筑物的高效能。芝加哥的110层的Sears Roebuck 总部大楼有9个筒体，从基础开始分成三个部分。这些独立筒体中的终端处在不同高度的建筑体中，这充分体现出了这种新式结构观念的建筑风格自由化的潜能。这座建筑物1450英尺(442米)高，是世界上最高的大厦。

薄壳筒体系统：这种筒体结构系统的设计是为了增强超高层建筑抵抗侧力的能力(风荷载和地震荷载)以及建筑的抗侧移能力。薄壳筒体是筒体系统的又一大飞跃。薄壳筒体的进步是利用高层建筑的正面(墙体和板)作为与筒体共同作用的结构构件，为高层建筑抵抗侧向荷载提供了一个有效的途径，而且可获得不用设柱，成本较低，使用面积与建筑面积之比又大的室内空间。

由于薄壳立面的贡献，整个框架筒的构件无需过大的质量。这样以来使得结构既轻巧又经济。所有的典型柱和窗下墙托梁都是轧制型材，最大程度上减小了组合构件的使用和耗费。托梁周围的厚度也可适当的减小。而可能占据宝贵空间的墙上镦梁的尺寸也可以最大程度地得到控制。这种结构体系已被建造在匹兹堡洲的One Mellon银行中心所运用。

钢筋混凝土中的各体系：虽然钢结构的高层建筑起步比较早，但是钢筋混凝土的高层建筑的发展非常快，无论在办公大楼还是公寓住宅方面都成为刚结构体系的有力竞争对手。

框架筒：像上面所提到的，框架筒构思首次被43层的迪威斯公寓大楼所采用。在这座大楼中，外柱的柱距为5.5英尺(1.68米)。而内柱则需要支撑8英寸厚的无梁板。

筒中筒结构：另一种针对于办公大楼的钢筋混凝土体系把传统的剪力墙结构与外框架筒相结合。该体系由柱距很小的外框架与围绕中心设备区的刚性剪力墙筒组成。这种筒中筒结构(如插图2)使得当前世界上最高的轻质混凝土大楼(在休斯顿建造的独壳购物中心大厦)的整体造价只与35层的传统剪力墙结构相当。

钢结构与混凝土结构的联合体系也有所发展。Skidmore ,Owings 和Merrill共同设计的混合体系就是一个好例子。在此体系中，外部的混凝土框架筒包围着内部的钢框架，从而结合了钢筋混凝土体系与钢结构体系各自的优点。在新奥尔良建造的52层的独壳广场大厦就是运用了这种体系。

钢结构是指在建筑物结构中钢材起着主导作用的结构，是一个很宽泛的概念。大部分的钢结构都包括建筑设计，工程技术、工艺。通常还包括以主梁、次梁、杆件，板等形

沈阳建筑工程学院毕业设计(论文) 44 式存在的钢的热轧加工工艺。上个世纪七十年代，除了对其他材料的需求在增长，钢结构仍然保持着对于来自美国、英国、日本、西德、法国等国家的钢材厂钢材的大量需求。

发展历史：早在Bessemer和Siemens-Marton(开放式炉)工艺出现以前，钢结构就已经有几十年的历史了。而直到此工艺问世之后才使得钢材可以大批生产出来供结构所用。对钢结构诸多问题的研究开始于铁结构的使用，当时很著名的研究对象是1977年在英国建造的横跨斯沃河的Coalbrook dale 大桥。这座大桥以及后来的铁桥设计再加上蒸汽锅炉、铁船身的设计都刺激了建筑安装设计以及连接工艺的发展。铁结构对材料的需求量较小是优胜于砖石结构的主要方面。长久以来一直用木材制作的三角桁架也换成铁制的了。承受由直接荷载产生的重力作用的受压构件常用铸铁制造，而承受由悬挂荷载产生的推力作用的受拉构件常用熟铁制造。

1851年英国的Joseph Paxtond为伦敦博览会建造了水晶宫。据说当时他已有这样的骨架结构构思：用比较细的铁梁作为玻璃幕墙的骨架。此建筑的风荷载抵抗力是由对角拉杆所提供的。在金属结构的发展历史中，有两个标志性事件：首先是从木桥发展而来的格构梁由木制转化为铁制;其次是锻铁制的受拉构件与铸铁制的受压构件受热后通过铆钉连接工艺的发展。

十九世纪五六十年代，Bessemer 与 Siemens-Martin工艺的发展使钢材的生产能满足结构的需求。钢的受拉强度与受压强度都好于铁。这种新型的金属常被有想象力的工程师所利用，尤其倍受那些参与过英国、欧洲以及美国的道桥建设的工程师的喜爱。

其中一个很好的例子就是Eads大桥(也被称为路易斯洲大桥)(1867-1874)。在这座大桥中，每隔500英尺(152.5米)设有由钢管加强肋形成的拱。英国的Firth of Forth悬索桥设有管件支撑，直径大约为12英尺(3.66米)，长度为350英尺(107)米。这些大桥以及其他结构在引导钢结构的发展，规范的实施，许用应力的设计方面起到了很重要的作用。1907年Quebec悬索大桥的偶然破坏揭露了二十世纪初期由于缺乏足够的理论知识，甚至是缺乏足够的理论研究的基础知识，而导致在应力分析方面出现了很多的不足。但是，这样的损坏却很少出现在金属骨架的办公大楼中。因为尽管在缺乏缜密的分析的情况下，这些建筑也表现出了很高的实用性。在上个世纪中叶，没有经过任何特殊合金强化、硬化过的普通碳素钢已经被广泛地使用了。

在1889年巴黎召开的世界博览会上，金属结构表现出了在超高层建筑运用上的内在潜力。在这次会上，法国著名的桥梁设计师埃非尔展示了他的杰作-300米高的露天开挖的铁塔。无论是它的高度(比著名的金字塔的两倍还高)，架设的速度-人数不多的工作人员

沈阳建筑工程学院毕业设计(论文) 45 仅用几个月的时间就完成了整个工程任务，还是很低的工程造价都使它脱颖而出。

首批摩天大厦：在刚结构发展的同时，美国的另一个是也蓬勃的发展起来了。1884-1885年，芝加哥的工程师Maj.William Le Baron Jennny设计了家庭保险公司大厦。这座大厦也是金属结构的，有十层高。大厦的梁是钢制的，而柱是铸铁所制。铸铁制的过梁支撑着窗洞口上方的砌体，同时也需要铸铁制的柱支撑着。实心砌体的天井与界墙提供抵抗风载的侧向支撑。不到十年的功夫，芝加哥和纽约已经有超过30座办公大楼是利用这种结构。钢材在这些结构中起了非常大的作用。这种结构利用铆钉把梁与柱连接在一起。有时为了抵抗风荷载还是在竖向构件和横向构件的连接点出贴覆上节点板来加固结构。此外，轻型的玻璃幕墙结构代替了老式的重质砌体结构。

尽管几十年来之中建筑形式主要是在美国发展的，但是它却影响着全世界钢材工业的发展。十九世纪的最后几年，基本结构形状工字型钢的厚度已经达到20英寸(0.508米)，非对称的Z字型钢和T型钢可以与有一定宽度和厚度的板相联结，使得构件具体符合要求的尺寸和强度。1885年最重的型钢通过热轧生产出来，每英寸不到100磅(45千克)。到二十世纪六十年代这个数字已经达到每英寸700磅(320千克)。

紧随着钢结构的发展，1988年第一部电梯问世了。安全载客电梯诞生，以及安全经济的钢结构设计方法的发展促使建筑高度迅猛增加。1902年在纽约建造的高286英寸(87.2米)的Flatiron大厦不断地被后来的建筑所超越。这些建筑分别是高375英尺(115米)的时代大厦(1904)，(后来改名为联合化工制品大厦)。1908年在华尔街建造的高468英尺(143米)的城市投资公司大厦，高612 英尺(187米)的星尔大厦，以及700英尺(214米)的都市塔和780英尺高(232米)的Woll worth大厦。

房屋高度与高宽比的不断增加也带来了许多的问题。为了控制道路的阻塞，要对建筑的缩进设计进行限定。侧向支撑的设置也是其中一项技术问题，例如，埃非尔铁塔所采用的对角支撑体系对于要靠太阳光来照明的办公大厦就不实用了。而只有考虑到具体的单独梁与单独柱的抗弯能力以及梁柱相交处的刚度的框架设计才是可靠的。随着现代内部采光体系的不断发展，抵抗风荷载的对角支撑又重新被利用起来了。芝加哥的John Hancock 中心就是一个很显著的例子。外部的对角支撑成为此结构立面的一个很显眼的部分。

第一次世界大战暂时中断了所谓摩天大厦(当时这个词并没有确定)的蓬勃发展，但是二十世纪二十年代又恢复了这一趋势。1931年建造的帝国大厦把词潮流推向了顶峰。102层高1250英尺(381米)的帝国大厦在后来的40年一直保持着世界最高的地位。它的建造速度充分证明了这种新的结构形式已经被当时的技术所掌握。次项工程所需要的梁

沈阳建筑工程学院毕业设计(论文) 46 是由Bayonne海湾对岸的军械库所提供的。是由用精密仪器控制的驳船和卡车负责运输的。由九架起重机将这些梁提升到指定的位置。由工业轨道装置把钢材和其他材料移到每一层上去。先是螺栓连接紧接着铆钉连接，最后是装修，整个工程的最终完成只用了一年零45天。

十九世纪末，利用焊接把各个钢零件相连接已取得了很好的成绩，并在第一次世界大战中被运用于救生船的修理。但直到第二次世界大战后才用于建筑结构中。同时在连接领域中又一进步就是高强螺栓代替了铆钉。

二战结束后，欧洲，美国，日本等国都扩大了对在不定应力(包括超过屈服点的情况)作用下各种结构钢的性质的研究，并进行了更为精确、系统的分析。此后，许多国家采用了一些更为自由灵活的设计规范和更为理想化的弹性设计规范。计算机在工程上的运用代替了冗长的手工计算，从而更加促进了钢结构的发展，并大大的减低了造价。

Talling building and Steel construction Although there have been many advancements in building construction technology in general. Spectacular archievements have been made in the design and construction of ultrahigh-rise buildings. The early development of high-rise buildings began with structural steel framing.Reinforced

沈阳建筑工程学院毕业设计(论文) 47 concrete and stressed-skin tube systems have since been economically and competitively used in a number of structures for both residential and commercial purposes.The high-rise buildings ranging from 50 to 110 stories that are being built all over the United States are the result of innovations and development of new structual systems. Greater height entails increased column and beam sizes to make buildings more rigid so that under wind load they will not sway beyond an acceptable limit.Excessive lateral sway may cause serious recurring damage to partitions,ceilings.and other architectural details. In addition,excessive sway may cause discomfort to the occupants of the building because their perception of such motion.Structural systems of reinforced concrete,as well as steel,take full advantage of inherent potential stiffness of the total building and therefore require additional stiffening to limit the sway. In a steel structure,for example,the economy can be defined in terms of the total average quantity of steel per square foot of floor area of the building.Curve A in Fig .1 represents the average unit weight of a conventional frame with increasing numbers of stories. Curve B represents the average steel weight if the frame is protected from all lateral loads. The gap between the upper boundary and the lower boundary represents the premium for height for the traditional column-and-beam frame.Structural engineers have developed structural systems with a view to eliminating this premium. Systems in steel. Tall buildings in steel developed as a result of several types of structural innovations. The innovations have been applied to the construction of both office and apartment buildings. Frame with rigid belt trusses. In order to tie the exterior columns of a frame structure to the interior vertical trusses,a system of rigid belt trusses at mid-height and at the top of the building may be used. A good example of this system is the First Wisconsin Bank Building(1974) in Milwaukee. Framed tube. The maximum efficiency of the total structure of a tall building, for both strength and stiffness,to resist wind load can be achieved only if all column element can be connected to each other in such a way that the entire building acts as a hollow tube or rigid box in projecting out of the ground. This particular structural system was probably used for the first time in the 43-story reinforced concrete DeWitt Chestnut Apartment Building in Chicago. The

沈阳建筑工程学院毕业设计(论文) 48 most significant use of this system is in the twin structural steel towers of the 110-story World Trade Center building in New York Column-diagonal truss tube. The exterior columns of a building can be spaced reasonably far apart and yet be made to work together as a tube by connecting them with diagonal members interesting at the centre line of the columns and beams. This simple yet extremely efficient system was used for the first time on the John Hancock Centre in Chicago, using as much steel as is normally needed for a traditional 40-story building. Bundled tube. With the continuing need for larger and taller buildings, the framed tube or the column-diagonal truss tube may be used in a bundled form to create larger tube envelopes while maintaining high efficiency. The 110-story Sears Roebuck Headquarters Building in Chicago has nine tube, bundled at the base of the building in three rows. Some of these individual tubes terminate at different heights of the building, demonstrating the unlimited architectural possibilities of this latest structural concept. The Sears tower, at a height of 1450 ft(442m), is the world’s tallest building.

Stressed-skin tube system. The tube structural system was developed for improving the resistance to lateral forces (wind and earthquake) and the control of drift (lateral building movement ) in high-rise building. The stressed-skin tube takes the tube system a step further. The development of the stressed-skin tube utilizes the façade of the building as a structural element which acts with the framed tube, thus providing an efficient way of resisting lateral loads in high-rise buildings, and resulting in cost-effective column-free interior space with a high ratio of net to gross floor area. Because of the contribution of the stressed-skin façade, the framed members of the tube require less mass, and are thus lighter and less expensive. All the typical columns and spandrel beams are standard rolled shapes,minimizing the use and cost of special built-up members. The depth requirement for the perimeter spandrel beams is also reduced, and the need for upset beams above floors, which would encroach on valuable space, is minimized. The structural system has been used on the 54-story One Mellon Bank Center in Pittburgh. Systems in concrete. While tall buildings constructed of steel had an early start, development of tall buildings of reinforced concrete progressed at a fast enough rate to provide a competitive chanllenge to structural steel systems for both office and apartment buildings.

沈阳建筑工程学院毕业设计(论文) 49 Framed tube. As discussed above, the first framed tube concept for tall buildings was used for the 43-story DeWitt Chestnut Apartment Building. In this building ,exterior columns were spaced at 5.5ft (1.68m) centers, and interior columns were used as needed to support the 8-in . -thick (20-m) flat-plate concrete slabs. Tube in tube. Another system in reinforced concrete for office buildings combines the traditional shear wall construction with an exterior framed tube. The system consists of an outer framed tube of very closely spaced columns and an interior rigid shear wall tube enclosing the central service area. The system (Fig .2), known as the tube-in-tube system , made it possible to design the world’s present tallest (714ft or 218m)lightweight concrete building ( the 52-story One Shell Plaza Building in Houston) for the unit price of a traditional shear wall structure of only 35 stories. Systems combining both concrete and steel have also been developed, an examle of which is the composite system developed by skidmore, Owings &Merril in which an exterior closely spaced framed tube in concrete envelops an interior steel framing, thereby combining the advantages of both reinforced concrete and structural steel systems. The 52-story One Shell Square Building in New Orleans is based on this system. Steel construction refers to a broad range of building construction in which steel plays the leading role. Most steel construction consists of large-scale buildings or engineering works, with the steel generally in the form of beams, girders, bars, plates, and other members shaped through the hot-rolled process. Despite the increased use of other materials, steel construction remained a major outlet for the steel industries of the U.S, U.K, U.S.S.R, Japan, West German, France, and other steel producers in the 1970s. Early history. The history of steel construction begins paradoxically several decades before the introduction of the Bessemer and the Siemens-Martin (openj-hearth) processes made it possible to produce steel in quantities sufficient for structure use. Many of problems of steel construction were studied earlier in connection with iron construction, which began with the Coalbrookdale Bridge, built in cast iron over the Severn River in England in 1777. This and subsequent iron bridge work, in addition to the construction of steam boilers and iron ship hulls , spurred the development of techniques for fabricating, designing, and jioning. The advantages of iron over masonry lay in the much smaller amounts of material required. The truss form, based

沈阳建筑工程学院毕业设计(论文) 50 on the resistance of the triangle to deformation, long used in timber, was translated effectively into iron, with cast iron being used for compression members-i.e, those bearing the weight of direct loading-and wrought iron being used for tension members-i.e, those bearing the pull of suspended loading. The technique for passing iron, heated to the plastic state, between rolls to form flat and rounded bars, was developed as early as 1800;by 1819 angle irons were rolled; and in 1849 the first I beams, 17.7 feet (5.4m) long , were fabricated as roof girders for a Paris railroad station. Two years later Joseph Paxton of England built the Crystal Palace for the London Exposition of 1851. He is said to have conceived the idea of cage construction-using relatively slender iron beams as a skeleton for the glass walls of a large, open structure. Resistance to wind forces in the Crystal palace was provided by diagonal iron rods. Two feature are particularly important in the history of metal construction; first, the use of latticed girder, which are small trusses, a form first developed in timber bridges and other structures and translated into metal by Paxton ; and second, the joining of wrought-iron tension members and cast-iron compression members by means of rivets inserted while hot. In 1853 the first metal floor beams were rolled for the Cooper Union Building in New York. In the light of the principal market demand for iron beams at the time, it is not surprising that the Cooper Union beams closely resembled railroad rails. The development of the Bessemer and Siemens-Martin processes in the 1850s and 1860s suddenly open the way to the use of steel for structural purpose. Stronger than iron in both tension and compression ,the newly available metal was seized on by imaginative engineers, notably by those involved in building the great number of heavy railroad bridges then in demand in Britain, Europe, and the U.S. A notable example was the Eads Bridge, also known as the St. Louis Bridge, in St. Louis (1867-1874), in which tubular steel ribs were used to form arches with a span of more than 500ft (152.5m). In Britain, the Firth of Forth cantilever bridge (1883-90) employed tubular struts, some 12 ft (3.66m) in diameter and 350 ft (107m) long. Such bridges and other structures were important in leading to the development and enforcement of standards and codification of permissible design stresses. The lack of adequate theoretical knowledge, and even of an adequate basis for theoretical studies, limited the value of stress analysis during the early years of the 20th

沈阳建筑工程学院毕业设计(论文) 51 century,as iccasionally failures,such as that of a cantilever bridge in Quebec in 1907,revealed.But failures were rare in the metal-skeleton office buildings;the simplicity of their design proved highly practical even in the absence of sophisticated analysis techniques. Throughout the first third of the century, ordinary carbon steel, without any special alloy strengthening or hardening, was universally used. The possibilities inherent in metal construction for high-rise building was demonstrated to the world by the Paris Exposition of 1889.for which Alexandre-Gustave Eiffel, a leading French bridge engineer, erected an openwork metal tower 300m (984 ft) high. Not only was the height-more than double that of the Great Pyramid-remarkable, but the speed of erection and low cost were even more so, a small crew completed the work in a few months.

The first skyscrapers. Meantime, in the United States another important development was taking place. In 1884-85 Maj. William Le Baron Jenney, a Chicago engineer , had designed the Home Insurance Building, ten stories high, with a metal skeleton. Jenney’s beams were of Bessemer steel, though his columns were cast iron. Cast iron lintels supporting masonry over window openings were, in turn, supported on the cast iron columns. Soild masonry court and party walls provided lateral support against wind loading. Within a decade the same type of construction had been used in more than 30 office buildings in Chicago and New York. Steel played a larger and larger role in these , with riveted connections for beams and columns, sometimes strengthened for wind bracing by overlaying gusset plates at the junction of vertical and horizontal members. Light masonry curtain walls, supported at each floor level, replaced the old heavy masonry curtain walls, supported at each floor level , replaced the old heavy masonry. Though the new construction form was to remain centred almost entirely in America for several decade, its impact on the steel industry was worldwide. By the last years of the 19th century, the basic structural shapes-I beams up to 20 in. ( 0.508m) in depth and Z and T shapes of lesser proportions were readily available, to combine with plates of several widths and thicknesses to make efficient members of any required size and strength. In 1885 the heaviest structural shape produced through hot-rolling weighed less than 100 pounds (45 kilograms) per foot; decade by decade this figure rose until in the 1960s it exceeded 700 pounds (320 kilograms) per foot. Coincident with the introduction of structural steel came the introduction of the Otis electric

沈阳建筑工程学院毕业设计(论文) 52 elevator in 1889. The demonstration of a safe passenger elevator, together with that of a safe and economical steel construction method, sent building heights soaring. In New York the 286-ft (87.2-m) Flatiron Building of 1902 was surpassed in 1904 by the 375-ft (115-m) Times Building ( renamed the Allied Chemical Building) , the 468-ft (143-m) City Investing Company Building in Wall Street, the 612-ft (187-m) Singer Building (1908), the 700-ft (214-m) Metropolitan Tower (1909) and, in 1913, the 780-ft (232-m) Woolworth Building. The rapid increase in height and the height-to-width ratio brought problems. To limit street congestion, building setback design was prescribed. On the technical side, the problem of lateral support was studied. A diagonal bracing system, such as that used in the Eiffel Tower, was not architecturally desirable in offices relying on sunlight for illumination. The answer was found in greater reliance on the bending resistance of certain individual beams and columns strategically designed into the skeletn frame, together with a high degree of rigidity sought at the junction of the beams and columns. With today’s modern interior lighting systems, however, diagonal bracing against wind loads has returned; one notable example is the John Hancock Center in Chicago, where the external X-braces form a dramatic part of the structure’s façade.

World War I brought an interruption to the boom in what had come to be called skyscrapers (the origin of the word is uncertain), but in the 1920s New York saw a resumption of the height race, culminating in the Empire State Building in the 1931. The Empire State’s 102 stories (1,250ft. [381m]) were to keep it established as the hightest building in the world for the next 40 years. Its speed of the erection demonstrated how thoroughly the new construction technique had been mastered. A depot across the bay at Bayonne, N.J., supplied the girders by lighter and truck on a schedule operated with millitary precision; nine derricks powerde by electric hoists lifted the girders to position; an industrial-railway setup moved steel and other material on each floor. Initial connections were made by bolting , closely followed by riveting, followed by masonry and finishing. The entire job was completed in one year and 45 days. The worldwide depression of the 1930s and World War II provided another interruption to steel construction development, but at the same time the introduction of welding to replace riveting provided an important advance. Joining of steel parts by metal are welding had been successfully achieved by the end of the 19th century and was used in emergency ship repairs during World War I, but its application to

沈阳建筑工程学院毕业设计(论文) 53 construction was limited until after World War II. Another advance in the same area had been the introduction of high-strength bolts to replace rivets in field connections. Since the close of World War II, research in Europe, the U.S., and Japan has greatly extended knowledge of the behavior of different types of structural steel under varying stresses, including those exceeding the yield point, making possible more refined and systematic analysis. This in turn has led to the adoption of more liberal design codes in most countries, more imaginative design made possible by so-called plastic design ?The introduction of the computer by short-cutting tedious paperwork, made further advances and savings possible.