机械工程英语第2版叶邦彦unit1

•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.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。

机械工程英语第二版叶邦彦陈统坚主编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。

Basic Concept in MechanicsThe branch of scientific analysis which deals with motions , time , and forces is called mechanics and is made up of two parts , statics and dynamics , Statics deals with the analysis of stationary systems , i.e. , those in which time is not a factor , and dynamics deals with systems which change with time .对运动、时间和作用力做出科学分析的分支称为力学。

它由静力学和动力学两部分组成。

静力学对静止系统进行分析，即在其中不考虑时间这个因素，动力学对随时间而变化的系统进行分析。

When a number of bodies are connected together to form a group or system , the forces of action and reaction between any two of the connecting bodies are called constraint forces . These forces constrain the bodies to behave in a specific manner . Forces external to this system of bodies are called applied forces .当一些物体连接在一起形成一个组合体或者系统时，任何两个相连接的物体之间的作用力和反作用力被称为约束力。

这些力约束着各个物体，使其处于特定的状态。

从外部施加到这个物体的系统的力被称为外力。

机械⼯程英语第2版叶邦彦Unit1Unit1 Advanced Engineering MaterialsTypes of materialsBy state：solid, liquid, or gasBy living：organic, inorganicBy industrial purposes：engineering materials.nonengineering materials.Engineering materialsused in manufacture and become parts of products.Nonengineering materialschemicals, fuels, lubricants, and other materials used inthe manufacturing process, which do not become part of the product.Engineering materials may be further subdivided into:MetalsCeramics(陶瓷)Composite(复合材料)Polymers(聚合体)othersMetals and Metal AlloysMetalsare elements that generally have good electrical and thermal conductivity.Many metals have high strength,high stiffness,and have good ductility.Some metals,such as iron,cobalt and nickel are magnetic（adj.有磁性的）.At extremely low temperatures,some metals and intermetallic compounds(⾦属间化合物)become superconductors.Differences between a metal alloy and a pure metalPure metals are elements which come from aparticular area of the periodic table.Examples：1. copper in electrical wires2. aluminum in cooking foil and beverage cans.Metal Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples ：1. stainless steel which is an alloy of iron, nickel, andchromium;2. gold jewelry which usually contains an alloy of goldand nickel.Some important properties of metalsDensity is defined as a material's mass divided by its volume. Most metals have relatively high densities,especially compared to polymers.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.Fracture Toughness can be described as a material‘s ability to avoid fracture,especially when a flaw is introduced.Plastic deformation is the ability of a material to bend or deform before breaking.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.However, sometimes we can take advantage of(利⽤)plastic deformation.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.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.The atomic bonding of metalsIn metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere. Since electrons conduct heatand electricity, metals make good cooking pans and electricalwires. It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal .[2]No photons pass through.Ceramics and GlassesA 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 (n.约定, 约束, 契约) that "ceramics" must also be crystalline.A glass is an inorganic nonmetallic material that does not have a crystalline (晶体) structure. Such materialsare said to be amorphous (⾮晶体).Properties of Ceramics and Glassesusual properties :high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.special properties:electrical and thermal insulators;magnetic materials;piezoelectric materials;superconductors at very low temperatures.Ceramics and glasses have one major drawback : they are brittle.Ceramics FormingCeramics are not typically formed from the melt. This is because most ceramics will crack extensively (i.e. form a powder)upon cooling from the liquid state. 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.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.Application ——An optical fiberAn 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 glass from scratches and other surface imperfections,and an outer polymer jacket to protect the fiber from damage.[4]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 s l o w e r,b u t d o e s n o t a b s o r b t h e l i g h t.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.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.Two types of CompositesFiber Reinforced Composites Particle Reinforced CompositesFiber Reinforced CompositesReinforcing fibers makeup：can be made of metals, ceramics, glasses, or polymers that havebeen turned into graphite and known as carbon fibers.Fibers advantages：increase the modulus of the matrix material. The strong covalent bonds along the fiber's length gives them a very high modulus inthis direction because to break or extend the fiber the bonds must also be broken or moved.Fibers disadvantage：As it is difficult to process into composites，making fiber-reinforced composites relatively expensive.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. Body parts of race cars and some automobiles are composites made of glass fibers in a thermoset matrix.。

Unit 2 Numerical Control of Production EquipmentUnit 2 生产设备的数字控制Numerical Control (NC) is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols. The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work-part or job. 数控是程序控制的自动化，在数字控制系统中，设备通过数字，字母和符号来编码，以一种合适的格式为每一个特定的零件或工件定义一个程序指令集。

When the job changes, the program of instructions is changed. The capability to change the program is what makes NC suitable for low-and medium-volume production. It is much easier to write new programs than to make major alterations of the processing equipment.当工件变化时，程序也变化，改变程序的能力亦适合中小批量生产。

写一个新程序比改变大量生产设备要容易的多。

Basic Components of NC数控基本结构A numerical control system consists of the following three basic components:数控系统由下面三部分组成：• Program of instructions控制程序• Machine control unit机器控制单元• Processing equipment加工设备The general relationship among the three components is illustrated in Fig. 2.1. The program is fed into the control unit, which directs the processing equipment accordingly.三部分的基本关系，由图 2.1 所示。

机械工程英语第二版第二部分翻译Unit 1Introduction前言The central and essential ingredient of GAD/CAMis the digital computer.〔1〕Its inherent speed and storage capacity have made it possible to achieve the advances in image processing, real-time process control, and a multitude of other important functions that are simply too complex and time-consuming to perform manually. To understand CAD/CAM it is important to be familiar with the concepts and technology of the digital computerCAD/CAM的重要组成部分是数字计算机，它固有的速度以及存储能力似的它能够在图像处理，实时过程控制以及很多因太复杂太费时而人工无法完成的其他重要功能方面获得进步，要想懂得CAD/CAM，熟悉数字电脑的概念和技术是很重要的.The modern digital computer is an electronic machine that can perform mathematical and logical calculations and data processing functions in accordance with a predetermined program of instructions. The computer itself is referred to as hardware, whereas the various programs are referred to as software.现在数字计算机是一部能够根据预定的程序来完成数字和逻辑运算以及数据处理功能的电子设备，计算机本身称为硬件，而各种各样的程序称为软件There are three basic hardware components of a general-purpose digital computer; 一般用途的数字计算机由三种基本硬件组成.Central processing unit (CPU) 微处理器.Memory存储器.Input/output ( I/0 )section输入/输出设备The relationship of these three components is illustrated in Fig. 1.1. The central processing unit is often considered to consist of two subsections; a control unit and an arithmetic-logic unit (ALU). 这三个组成部分的关系如图1.1所示，中央处理器通常被认为包含两部分:一个控制器和一个运算器.The control unit coordinates the operations of all the other components. 控制器控制所有其他组成部分的运输。

Unit 2 Numerical Control of Production EquipmentUnit 2 生产设备的数字控制Numerical Control (NC) is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols. The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work-part or job. 数控是程序控制的自动化，在数字控制系统中，设备通过数字，字母和符号来编码，以一种合适的格式为每一个特定的零件或工件定义一个程序指令集。

When the job changes, the program of instructions is changed. The capability to change the program is what makes NC suitable for low-and medium-volume production. It is much easier to write new programs than to make major alterations of the processing equipment.当工件变化时，程序也变化，改变程序的能力亦适合中小批量生产。

写一个新程序比改变大量生产设备要容易的多。

Basic Components of NC数控基本结构A numerical control system consists of the following three basic components:数控系统由下面三部分组成：• Program of instructions控制程序• Machine control unit机器控制单元• Processing equipment加工设备The general relationship among the three components is illustrated in Fig. 2.1. The program is fed into the control unit, which directs the processing equipment accordingly.三部分的基本关系，由图 2.1 所示。

Unit 1 计算机技术1、The central and essential ingredient of GAD/CAM is the digital computer. CAD/CAM的核心部分是数字计算机。

2、Sinfnal conditioners,which filter random electrical noise and smooth the signal emanating from transducting devices.信号调整器，它可以过滤掉杂乱的电噪声，并可修整、平滑由传感装置送出的模拟信号。

3、A pulse counter is used to convert the pulse trains into a digital representation ,which is then aplied to the computer”s input channel. 脉冲计数器可将脉冲串转换为一种数字代码，以适合于计算机输入通道。

4、This results from the shared nature of the communication lines.这来自通信线的共享特性。

5、messages to a specific computer are usually transmitted to all computers in the network,with the addressee decoding its address and accdot the information.送往某特定计算机的信息，一般都传送到网络中的所有计算机，同时由信息接收计算机译出地址码并接收信息。

6、In a network,all computers are connected and communicated with each other according to some kinds of enacthed regulations or agreement,which are called"network protocols".在网络中，所有计算机都根据一些规则和协议进行连接和通信，规则和协议称为网络协议。

•Types of Materials 第一单元Unit1 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.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。

机械工程英语第2版叶邦彦Unit2Unit 2 Heat Treatment of Metals What is heat treatment ？Iron-Carbon Diagram AnalysisHeat Treatment TechniquesWhat is heat treatment ？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.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.Heat Treatment ApplicationMay remove internal stressesMay reduce grain sizeMay increase toughnessMay produce a hard surface on a ductile interiorThe analysis of the steel must be known because small percentages of certain elements, notably carbon, greatly affect the physical properties.Alloy steels owe their properties to the presence of one or more elements other than carbon, namely nickel, chromium , manganese, molybdenum , tungsten, silicon, vanadium , and copper.[1] Because of their improved physical properties they are used commercially in many ways not possible with carbon steels.Iron-Carbon Diagram AnalysisThose portions of the iron-carbon diagram near thedelta region and those above 2% carbon content are of little importance to the engineer and are deleted.[2] A simplified diagram, such as Fig.2.1, focuses on theeutectoid region and is quite useful in understanding the properties and processing of steel.The key transition described in this diagram is the decomposition of single-phase austenite (Y) to the two-phase ferrite plus carbide structure as temperature drops.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 .The transition processAt 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 . 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. [3]The rejected carbonforms the carbon-richcementite intermetallicwith composition Fe3C.In essence, the netreaction at the eutectoidaustenite ：0.77%Cferrite：0.02%Ccementite：6.67%CFig.2.1 Simplified ion-carbon diagramSince 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 alternating plates that forms on slow cooling.Heat Treatment Techniques HardeningTemperingAnnealingNormalizingSpheroidizingSurface HardeningHardeningDefinition：Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.Influencing factors:1.the correct temperature is obtained.2.the rate of heating is important.3.The hardness obtained from a given treatment dependson the quenching rate, the carbon content, and work size.TemperingSteel 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 forservice conditions. 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. The final structure obtained from tempering fully hardened steel is called tempered martensite.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.AnnealingThe primary purpose of annealing is to soften hard steelso that it may be machined or cold worked. This is usually accomplished by heating the steel too slightly above the critical temperature, holding it there until the temperatureof 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.Annealing effectswipes out all trace of previous structure；refines the crystalline structure；softens the metal；relieves internal stresses previously set up in the metal.The temperature to which given steel should be heated in annealing depends on its composition; for carbon steels it can beobtained readily from the partial iron-iron carbide equilibrium diagram. 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.NormalizingThe 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. 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.SpheroidizingSpheroidizing is the process of producing astructure 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.Methods Of Surface HardeningCarburizingCarbonitridingCyaniding [氰化]Nitriding [渗氮]CarburizingThe 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.Thecarbon is absorbed into the metal to form a solid solution with iron and converts the outer surface into high-carbon steel.Pack carburizing consists of placing the parts to be treated in a closed container with some carbonaceous material such as charcoal or coke.。

《机械专业外语》课程教学大纲课程类别：专业选修课适用专业：机械制造与自动化适用层次：高起专适用教育形式：成人教育考核形式：考查所属学院：制造科学与工程学院先修课程：机械设计基础、机械制造基础、工程材料等一、课程简介本课程是机械设计制造及其自动化专业本科生开设的专业选修课。

本课程兼顾英语语言的学习、应用和机械设计制造及其自动化专业知识三个方面的知识。

旨在培养学生在机械设计制造实践中应用英语的能力，同时强化学生对机械设计制造及其自动化专业术语、基本概念和理论的掌握。

内容包括机械设计，加工方法，工程材料和先进制造技术等，涉及面广，专业性强。

二、课程学习目标本课程为以提高学生机械类专业英语阅读和翻译能力为主要目标。

通过本课程的学习，使学生显著提高学生阅读原文专业书刊和翻译国外设备技术文件的能力，同时巩固和加深已有专业知识，了解本学科的发展前沿及国外本学科领域的发展趋势。

(一)知识目标1)使学生掌握机电专业领域的一些常用词汇、词组和特殊句型结构;2)使学生了解专业英语的特点及语法结构特点;3)掌握基本的英语语法规则,并能运用所学的语法知识;4)使学生掌握专业英语的翻译技巧,能基本学会涉及专业业务的结构简单的日常语言的翻译。

(二)能力目标1)使学生理解阅读相关专业一般难度英文材料的能力;2)具有进行简单的专业英语交流的能力；3)使学生借助词典能够阅读本专业领域中等难度的英语文章;4)翻译英文文章的能力；5)拓展学生运用英语进行交际的范围和继续学习的能力。

(三)素质目标1)使学生在学习过程中增进对国外机电专业知识的了解;激发学生的学习兴趣;发展学生的智力,提高他们的观察、注意、记忆、思维、想象、联想等能力;2)通过知识教学的过程培养学生自学能力;3)培养学生的创新精神和实践能力,努力为学生的终身发展奠定语言基础和专业基础;4)培养学生善于沟通交流和团队协助的能力。

三、与其他课程的关系本课程是学生在完成公共英语学习基础上的英语继续学习,学习了机械设计基础、机械制造技术基础、工程材料等专业课基础上开设的一门专业课,具备一定专业知识后在学习该课程能够使学生比较容易接受,教学环节顺序进行。

Types‎ of Mater‎i als材料的类型‎Mater‎ials may be group‎ed in sever‎al ways. Scien‎tists‎ often‎ class‎ify mater‎ials by their‎ state‎: solid‎, liqui ‎d, 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. Engin ‎e erin‎g 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 proce ‎s s, 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。