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Unit 1 材料的种类（1）材料的分类方法很多。
科学家常用的典型的方法是根据它们的状态分类：固体，液态或气态。
材料也分为有机（可再生）和无机材料（不可再生）。
（2）工业上，材料划分为工程材料或非工程材料。
工程材料用于制造和加工成零件的材料。
非工程材料是化学药品，燃料，润滑剂和其它用于制造又不用来加工成零件的材料。
（3）工程材料可进一步细分为：金属，陶瓷，复合材料，聚合材料，等。
Metals and Metal Alloys 金属和金属合金金属和金属合（4）金属有好的导电好导热性，很多金属有高的强度，高硬度和高的延展性。
象铁，钴，镍这些金属有磁性。
在非常低的温度下，一些金属和金属互化物变成超导体。
（5）合金和纯金属有什么区别？纯金属在元素周期表的特殊区域。
例如用于制造电线的铜和做锅和饮料罐的铝。
合金含有两种以上的金属元素。
改变金属元素的比例可以改变合金的性质。
例如，合金金属的不锈钢，是由铁，镍，和铬组成。
而黄金珠宝含有金镍合金。
（6）为什么要使用金属和合金？很多金属和合金有很高密度并用在要求质量与体积比高的的场合。
一些金属合金，象铝基合金，密度低，用在航空领域可以节省燃料。
很多合金有断裂韧度，可以承受冲击，且耐用。
金属有哪些重要属性？（7）【密度】质量除以体积叫做密度。
很多金属有相对高的密度,特别的，象聚合体。
高密度的材料常是原子量很大，象金或铅。
然而一些金属，像铝或镁密度低，就常常用在要求有金属特性而又要求低质量的场合。
（8）【断裂韧性】断裂韧度用来描述金属抗断裂的能力，特别的，当有裂纹时。
金属通常都有无关紧要的刻痕和凹坑，且有耐冲击性。
足球队员关注这一点当他确信面罩不会被击碎的时候。
（9）【塑形变形】塑性变形表述的是材料在断裂之前弯曲变形的能力。
作为工程师，我们通常设计材料使得能够在正常情况下不变形。
你不会想要一阵强烈的西风就把你的车刮得往东倾斜。
然而，有时，我们可以利用塑性变形。
汽车的承受极限就是在彻底破坏之前靠塑形变形来吸收能量。
•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。
单词：The vertical turning and boring mill 立式车床和钻铣Automatic lathes 自动车床Longitudinal & transverse feed control 纵向和横向进给控制infinitely variable spindle speed 无限可变转速through hole 通孔bar stock 棒料engine lathe 普通车床tapered 锥形的alignment 同轴性turret lathe 六角车床twist drill 麻花钻screw thread 螺纹keyway 键槽vertical 垂直machine tool 机床horizontal 水平stress 应力strain 应变productivity生产力torque 转矩contour轮廓introduction导言plastic deformation 塑性变形metal alloys 金属合金Investment casting 熔模铸造Centrifugal Casting 离心铸造Powder consolidation粉末固化Sintering烧结Rake angle前角Chip formation切削形成汉译英Engineering materials工程材料Heat treatment of metals金属热处理Casting process铸造工艺Forging process锻造工艺Powder metallurgy粉末冶金Injection molding喷射模塑法Metal cutting金属切削Grinding磨削Lapping and polishing研磨和抛光Surface engineering表面处理Lathe and turning车床和车削Drilling and milling钻和铣第一单元•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。
Unit 9 Computer-Integrated Manufacturing System COMPUTER INTEGRATED MANUFACTURING SYSTEM (1)计算机集成技术CIM DEFINEDComputer-integrated manufacturing or (CIM) is the term used to describe the most modern ap-proach to manufacturing. Although CIM encompasses many of the other advanced manufacturingtechnologies such as computer numerical control (CNC) ,computer-aided design/computer-aidedmanufacturing (CAD/CAM)。
robotics，and just一in-time delivery (J1T)，it is more than a newtechnology or a new concept. Computer-integrated manufacturing is actually an entirely new ap-proach to manufacturing a new way of doing business.计算机集成制造(或CIM)是用来描述最现代化的一种制造方法的词汇。
尽管CIM包含了许多其他的先进制造技术,如计算机数字控制(CNC),计算机辅助设计/计算机辅助制造(CAD / CAM),机器人学和及时供货等,但它不仅仅是一种更高层次新技术或新概念。
计算机集成制造实际上是一种全新的制造方法和一种全新的贸易方式。
To understand CIM，it is necessary to begin with a comparison of modern and traditionalmanufacturing. Modern manufacturing encompasses ail of the activities andprocesses necessary to convert raw materials into finished products, deliver them to the market,and support them in thefield'. These activities include the following为了理解CIM，有必要一开始就有一个现代和传统制造业的比较。
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。
Unit 1Advanced Engineering MaterialsCeramic 陶瓷Organic 有机的Inorganic 无机的Composite 复合材料Lubricant 润滑剂Alloy 合金Conuctivity 传导性Stiffness 刚度Ductility 韧性Cobalt 钴Nickel 镍Aluminum 铝Beverange 饮料Chromium 铬Impact 撞击力Polymer 聚合材料Atom 原子Atomic 原子的Magnisum 镁Flaw 裂纹Nick 刻痕Dent 压痕Shatter 毁损Crumple 皱折Valence 化合价Fracture toughness 断裂韧性Be grouped 归类Be divided into 划分Plastic deformation 塑性变形Be subdivided into 细分，再分Separate …into…分开，分类Unit2Heat Treatment of MetalsHardening 淬火Carbide 硬质合金Preliminary 初步的Specimen 样品Microscopic 显微镜的Rate 速率Flow 流动Exterior 外部Interior 内部Definite 确切的Uniform 一致的Eliminate 排除Warp 变形，扭曲Crack 开裂Partially 部分的Eutectoid 共析的Pearlite 珠光体Cementite 渗碳体Anneal 退火Medium 媒介Brine 盐水Finite 有限的Drawing 轧制Tensile 可拉长的Martensite 马氏体Precipitation 析出、沉淀Agglomeration 凝聚Coalescence 联合，聚并Substantial 大量的Austempering 奥氏回火法Martempering 马氏回火法Critical range 临界范围，临界期Heat quench 热淬火All the more 更加Close control 精确控制Unit 3 CastingProcessesBronze 青铜Brass 黄铜Molten 熔铸的Synthetic 合成的，人造的Pattern 模子Sprue 浇注口Runner 浇道Approximate 近似的Duplicate 复制品Aggregate 集合，总计Flask 沙箱Core 型芯Riser 冒口V oid 空隙Shrink 收缩Cope 上箱Drag 下箱Facilitate 使便利Draft 拔模余量Angular 有角度的Offset 偏移Vertical 垂直的Minimum 最小值Horizontal 水平的Portion 部分Gateway浇口Vent 通气孔Contraction 收缩Linear 线性的Shrinkage 缩水，收缩Sand casting 砂型铸造Core print 型芯头Parting line 分型线Parting face 分型面Machining（finish）allowance加工余量Unit4 2ForgingProcessescomprehensive 有压力的comprise 包含anvil 铁砧semimechanized 半机械化的elongation 拉伸lateral 横向的upsetting 顶锻bar 棒料axially 轴向的complexity 复杂性giant 巨大的hydraulically 液压的marine 航海的，船舶的propeller 螺旋推进器shaft 轴squeeze 挤，压榨ingot 锭铁refine 精炼randomly 随便地，未加计划地oriented 导向的，使适应，使确定方向porosity 多孔性hot-forming 热成型open-die forging 开模锻造close-die forging 闭模锻造jet-aircraft 喷气式飞机marine propeller shaft 螺旋桨轴drop-forge 冲锻，落锤锻造be oriented in 定……的方位Unit 5 Power Metallurgysinter 烧结coalesce 熔合ferrous 铁的，含铁的resultant 因而发生的，必然产生的homogeneous 同类的，相似的，均一的compromise 折衷的blend 混合glue 胶水theoretical 理论上的segregation 隔离diffusion 扩散，传播article 物品fabrication 编造，虚构捏造，伪造whilst 同时，时时bush 衬套bearing 轴承ferrous and nonferrousmetals 黑色及有色金属bush type bearing 滑动轴承a mass of 一堆，块，大量，大批，众多Unit 6 InjectionMoldingresin 树脂woven 机织织物mat 席子molecule 分子entity 实体，机构analogy 类似，类推，模拟，比喻differentiate 区别，区分thermoset 热固性incident 入射光opaque 不透明的solvent 溶剂fatigue 疲劳polycarbonate 聚碳酸酯transparent 透明的abrasive 研磨剂qualitatively 定性地beam 横梁specimen 样本deflection 挠度，偏差chamical bond 化学键impact strength 冲击强度incident light 入射光short-chopped fiber短纤维Unit 7 Metal Cuttingnormal 垂直的rake条，货架clearance 间隙，裕量backup 阻塞dissipation 消散rub 摩擦severe 严重的, 剧烈的adjacent 邻近的revolution 周期stroke 冲程，行程schematically 用图示法地elastically 有弹性地shear 剪切considerable 不可忽视的，相当大的curvature 弯曲，曲率rake angle 前角rake face 前刀面mild steel 中碳钢clearance angle 后角flank face 后刀面feed rate 进给量chip curl 切屑螺旋Unit 8 Grindingabrasive 有研磨作用的cylindrical 圆柱的spindle 转轴horizontal水平的vertical 竖直的planer 刨床reciprocating 往复式table 工作台periphery 圆周，边缘fixture 工件夹具chuck 吸盘center 顶尖transverse 横向的longitudinal 纵向的strap n.带, 皮带；vt. (用皮带)捆扎damp 夹紧，夹住planetary 行星的spin 使转动tilt 倾斜的resolve 分解parallel 平行的milling cutter 铣刀cylindrical surface 柱面cylindrical grinding machine 外圆磨床strap clamp 压板cylindrical grinding外圆磨削internal grinding 内圆磨削depth of cut 背吃刀量plunge cut 切入磨削rest blade 托板rubber-bonded 橡胶胶合Unit 9 Lappingand Polishinglapping 研磨polishing 抛光lap 研具embedded 压入的slurry 悬浮液piston 活塞cylinder 汽缸peak 凸峰valley 凹陷scratch 划痕pit 凹坑，蚀坑plateau 平台，高原spherical 球面的curvy 弯曲的lustrous 有光泽的mechanism 机构，机械装置smear 磨平，抹平electropolishing 电解抛光electroplating 电镀ion 离子electrolysis 电解electrolyte 电解质，电解液anodic 阳极的catholic 阴极的dissolution 溶解，融化fabrication 制造，生产，加工wafer 薄板resilient 有回弹力的reagent 试剂silicon 硅multiphase 多方面的dynamic 动力desorption解吸附作用compositive 合成的cast iron 生铁，铸铁，machining mark 机械加工痕迹surface irregularity 表面不平度mountain ranges 山脉ground down 碾碎glass lenses 玻璃透镜fine scale 精密标度mirror-like 镜似的finishing techniques 加工技巧direct electrical current 直流电metallic salt 金属盐类chemical mechanical polishing化学机械抛光damage-free 不受损伤integrated circuit 集成电路active compound 有效成分oxidation-reductive 氧化还原的Unit10 Surface。
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。
Unit 9 Computer-IntegratedManufacturing System[计算机集成制造系统]CIM DefinedModern manufacturing encompasses all of the activities and process necessary to convert raw materials into finished products,deliver them to the market,and support them in the field.These activities include the following(Fig.9.1).(1) Identifying a need for a product(2) Designing a product to meet the needs(3) Obtaining the raw materials needs to produce the product(4) Applying appropriate processes to transform the raw materialsinto finished products(5) Transporting products to the market(6) Maintaining the products to ensure a proper performance inthe field.Historical Development of CIMManufacturing has evolved through four distinct stages ( Fig.9.2 )Fig.9.2 Historical development of integrated manufacturingStage1 Manual ManufacturingStage2 Mechanization / Specialization Stage3 AutomationStage4 IntegrationProblems Associated with CIM Technological Problems of CIM Cultural Problems of CIMBusiness-Related Problems of CIMComposition of CIMThe Computer and Automated Systems Association of the Society of Manufacturing Engineers(CASA/SME)developed the CIM wheel to include five distinct components:(Fig.9.3)(1) General business management(2) Product and process definition(3) Manufacturing planning and control(4) Factory automation(5) Information resource managementBenefits of CIMProduct quality increasesLead times are reducedDirect labor costs are reduced Product development cost time is reducedInventories are reducedOverall productivity increases Design quality increases The dolly is distributing some goods on the fixed pointA robot is working on the product lineFig.9.1 Modern CIM system.A research center of CIM in the Tsinghua UniversityManual manufacturing using simple hand tools was actually integrated manufacturing.All information needed to design,produce,and deliver a product was readily available because it resided in the mind of the person who performed all of the necessary tasks.Instead of one person designing,producing,and delivering a product,workers and/or machines performed specialized tasks within each of these broad areas.Automation improved the performance and enhanced the capabilities of both people and machines within specialized manufacturing components.With the advent of the computer age,manufacturing has developed full circle.It began as a totally integrated concept and,with CIM,has once again become one.CIM is not just new manufacturing technology,it is a whole new approach to manufacturing a new way of doing business. As a result,many people reject for the new approach represented by CIM for a variety of reasons.Traditional accounting practices do not work with CIM. There is no way to justify CIM based on traditional accounting practices.Therefore,it can be difficult to convince traditional business people,who are used to relying on traditional accounting practices,to see that CIM is an approach worth the investment.Fig.9.3 CIM wheelNotes1. Although CIM encompasses many of the other advancedmanufacturing technologies such as computer numericalcontrol(CNC). Computer-aided design/computer-aidedmanufacturing(CAD/CAM),robotics, and just-in-time delivery(JIT) it is more than a new technology or a new concept.句意：尽管CIM包含现有的很多先进制造技术，诸如计算机数控、计算机辅助设计或辅助制造、机器人学和及时供货等，但它不只是一种更高层次的新技术或新概念。
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。
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.。
Unit1 Advanced Engineering MaterialsTypes 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2版叶邦彦Unit13Unit 13Jigs and Fixtures1.Introduction2.Definition of a Drill Jig3.Typical Jigs and Fixtures1.IntroductionJigs and fixtures are alike in that they both incorporate [包含] devices to ensure that the workpiece is correctly located and clamped, but they differ in that :●Jigs incorporate means of tool guiding during the actualcutting operation, and fixtures do not.●Fixtures may incorporate means of setting the cuttingtools relative the location system.The advantages of jigs and fixtures can be summarised as follows:(1)marking out and other measuring and setting out methods areeliminated;(2)unskilled workers may proceed confidently and quickly in theknowledge that the workpiece can be positioned correctly, andthe tools guided or set;(3)the assembly of pairs is facilitated, since all components will beidentical within small limits, and “trying” and filing of work iseliminated;(4)the pairs will be interchangeable, and if the product is sold over awide area, the problem of spare parts will be simplified.The location of workpieceFig.1 represents a body thatis completely free in space. Inthis condition it has sixdegrees of freedom.Fig.1 The six degrees of freedom The clamping [夹持] of the workpieceThe clamping system must be such that the workpiece is held against the cutting forces, and the clamping forces must not be so great as to cause the workpiece to become distorted or damaged.2. Definition of a Drill JigA drill jig is a device for ensuring that a hole to bedrilled, tapped, or reamed in a workpiece will bemachined in the proper place.[3]Basically it consists of a clamping device to hold thepart in position under hardened-steel bushings throughwhich the drill passes during the drilling operation.3. Typical Jigs and FixturesTypical drill jigFig.2 illustrates a drillingjig for drilling four holes inthe flange [凸缘] of awork-piece that has beencompleted expect for thefour holes.Fig.2 Drilling jigTypical milling fixtureFig.3illustrates a simple milling fixture for milling the slot in the oterwise complited workpiece shown.The workpiece is clamped in position,and cutter is located against the setting block,which provides setting or cutter position and depth of cut .The fixture must be positioned relative to the machine table,this is done by engaging the two tenons at the bottom of the fixture in the slot in the machinetable[8] .the fixture is secured to the machine table with T-bolts,also engaging in the slots in the table (Fig.3).Fig.3 Milling fixtureNotes1. In practice,the only cutting tools that can be guided while actuallycutting are drills,reamers,and similar cutters;and so jigs are associated with drilling operations,and fixtures with all other operations.句意：实际上，在切削时惟一的能被引导的切削刀具是钻头、铰刀和类似的铣刀；因此钻模适用于钻削加工，而夹具则用在其他加工工艺中。
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。
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Spur GearsGears , defined as toothed members transmitting rotary motion from one shaft to another , are among the oldest devices and inventions of man . In about 2600 B.C. , the Chinese are known to have used a chariot incorporating a complex series of gears . Aristotle , in the fourth century B.C. , wrote of gears as if they were commonplace . In the fifteenth century A.D. , Leonardo da Vinci designed a multitude of devices incorporating many kinds of gears .齿轮，在最古老的设备和发明人中，被定义为通过轮齿将旋转运动从一根轴传递到另一根轴，大约在公元前2600年，中国人就知道用战车组成一系列复杂的齿轮系。
西元前四世纪，亚里士多德记述了齿轮就好像是他们司空见惯的一样。
在十五世纪，达芬奇设计了大量的包含各种各样齿轮的设备。
Among the various means of mechanical power transmission (including primarily gears , belts , and chains ) , gears are generally the most rugged and durable . Their power transmission efficiency is as high as 98 percent . On the other hand , gears are usually more costly than chains and belts . As would be expected , gear manufacturing costs increase sharply with increased precision -- as required for the combination of high speeds and heavy loads , and for low noise levels . ( Standard tolerances for various degrees of manufacturing precision have been established by the AGMA , American Gear Manufacturers Association. )在众多的机械传动方式中（包括齿轮传动，带传动，链传动），一般来说，齿轮是最经久耐用的，它的能量传递效率高达98%。
1.With low-power machinery or vehicles the operator can usually apply sufficient force through a simple mechanical linkage from the pedle or handle to the stationary part of the brake. In many cases, however, this force must be multiplied by using an elaborate braking system.（P5）用低能机器或传力工具，操作者通过向踏板或把手的一个简单机械连接构件作用足够的力量到车闸固定的部分。
大多数情况，然而，用一个详细（复杂）的车闸系统使这个力量成倍增加。
2. The fundamental principle involved is the use of compressed air acting through a piston in a cylinder to set block brakes on the wheels. The action is simultaneous on the wheels of all the cars in the train. The compressed air is carried through a strong hose from car to car with couplings between cars; its release to all the separate block brake units, at the same time, is controlled by the engineer. (Braking Systems)（P5）相关的基本原理是使用压缩气体，通过气缸内的活塞将闸块压在车轮起作用。
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。
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。
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 andnickel.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?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. 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。
