机电专业英语第2版1Unit-1-Engineering-Materials-工程材料

EngineeringMaterialsUnit1工程材料第2/49页机电专业英语徐存善主编上一页下一页TestingBeforeClass：Whichstateofironhascommercialuse(radio)铁的哪种状态有商业用途(单选)：提交第3/49页机电专业英语徐存善主编上一页下一页EngineeringMaterials第4/49页机电专业英语徐存善主编上一页下一页EngineeringMaterials第5/49页Text上一页下一页机电专业英语徐存善主编Inthedesignandmanufactureofaproduct,itisessentialthatthematerialandtheprocessbeunderstood.Materialsdifferwidelyinphysicalproperties,machinabilitycharacteristics,methodsofforming,andpossibleservicelife.Thedesignershouldconsiderthesefactsinselectinganeconomicalmaterialandaprocessthatisbestsuitedtotheproduct.Engineeringmaterialsareoftwobasictypes:metallicornonmetallic.Nonmetallicmaterialsarefurtherclassifiedasorganicorinorganicsubstances.Sincethereisaninfinitenumberofnonmetallicmaterialsaswellaspureandalloyedmetals,considerablestudyisnecessarytochoosetheappropriateone.第6/49页Text上一页下一页机电专业英语徐存善主编Fewcommercialmaterialsexistaselementsinnature.Forexample,thenaturalcompoundsofmetals,suchasoxides,sulfides,orcarbonates,mustundergoaseparatingorrefiningoperationbeforetheycanbefurtherprocessed.Onceseparated,theymusthaveanatomicstructurethatisstableatordinarytemperaturesoveraprolongedperiod.Inmetalworking,ironisthemostimportantnaturalelement.Ironhaslittlecommercialuseinitspurestate,butwhencombinedwithotherelementsintovariousalloysitbecomestheleadingengineeringmetal.Thenonferrousmetals,includingcopper,tin,zinc,nickel,magnesium,aluminum,lead,andothersallplayanimportantpartinoureconomy;eachhasspecificpropertiesanduses.第7/49页Text上一页下一页机电专业英语徐存善主编Manufacturingrequirestoolsandmachinesthatcanproduceeconomicallyandaccurately.Economydependsontheproperselectionofthemachineorprocessthatwillgiveasatisfactoryfinishedproduct,itsoptimumoperation,andmaximumperformanceoflaborandsupportfacilities.Theselectionisinfluencedbythequantityofitemstobeproduced.Usuallythereisonemachinebestsuitedforacertainoutput.第8/49页Text上一页下一页机电专业英语徐存善主编Insmall-lotorjobshopmanufacturing,general-purposemachinessuchasthelathe,drillpress,andmillingmachinemayprovetobethebestbecausetheyareadaptable,havelowerinitialcost,requirelessmaintenance,andpossesstheflexibilitytomeetchangingconditions.However,aspecial-purposemachineshouldbeconsideredforlargequantitiesofastandardizedproduct.Amachinebuiltforonetypeofworkoroperation,suchasthegrindingofapistonorthesurfacingofacylinderhead,willdothejobwell,quickly,andatlowcostwithasemiskilledoperator.第9/49页Text上一页下一页机电专业英语徐存善主编Manyspecial-purposemachinesortoolsdifferfromthestandardtypeinthattheyhavebuiltintothemsomeoftheskilloftheoperator.Asimpleboltmaybeproducedoneitheralatheoranautomaticscrewmachine.Thelatheoperatormustknownotonlyhowtomaketheboltbutmustalsobesufficientlyskilledtooperatethemachine.Ontheautomaticmachinethesequenceofoperationsandmovementsoftoolsarecontrolledbycamsandstops,andeachitemproducedisidenticalwiththepreviousone.Thistransferofskillintothemachine,orautomation,allowslessskillfuloperatorsbutdoesrequiregreaterskillinsupervisionandmaintenance.Oftenitisuneconomicaltomakeamachinecompletelyautomatic,becausethecostmaybecomeprohibitive.第10/49页Text上一页下一页机电专业英语徐存善主编Theselectionofthebestmachineorprocessforagivenproductrequiresknowledgeofproductionmethods.Factorsthatmustbeconsideredarevolumeofproduction,qualityofthefinishedproduct,andtheadvantagesandlimitationsoftheequipmentcapableofdoingthework.Mostpartscanbeproducedbyseveralmethods,butusuallythereisonewaythatismosteconomical.第11/49页NewwordsandphrasesText上一页下一页机电专业英语徐存善主编machinability[mə,ʃi:nə'biləti]n.可加工性，可切削性，机械加工性characteristic[,kærəktə'ristik]adj.典型的，特有的n.特征,特性metallic[mi'tælik,me-]adj.金属的，含金属的n.金属纤维nonmetallic[,nɔnmi'tælik]adj.非金属的n.非金属物质organic[ɔ:'ɡænik]adj.有机的,组织的,器官的infinite['infinət]adj.无穷的，极大的n.无限，无穷大alloyed['ælɔid,ə'l-]adj.合金的；合铸的；熔合的vt.将…铸成合金appropriate[ə'prəuprieit,ə'prəupriət]adj.适当的,合适的vt.占用,拨出commercial[kə'mə:ʃəl]adj．商业上的，商业的n.商业广告compound['kɔmpaund,kə-]n.化合物vt.合成vi.和解adj.复合的oxide['ɔksaid]n．氧化物，氧化层，氧化合物第12/49页NewwordsandphrasesText上一页下一页机电专业英语徐存善主编sulfide['sʌlfaid]n．硫化物，含硫系列，硫醚carbonate['kɑ:bəneit]n．碳酸盐vt.使充满二氧化碳，使变成碳酸盐undergo[,ʌndə'ɡəu]vt.经历，经受；忍受prolonged[prəu'lɔŋd,-'lɔ:-]adj.延长的，拖延的，持续很久的iron['aiən]n.铁，熨斗；烙铁adj.铁的；刚强的optimum['ɔptiməm]n．最佳效果,最适合条件adj.最适宜的influence['influəns]n.影响，势力，有影响的人或事vt.影响；改变flexibility[,fleksi'biliti]n．机动性，灵活性，适应性cam[kæm]n.凸轮，偏心轮vt.给(机器)配置偏心轮supervision[,sju:pə'viʒən]n．监督，管理；指导第13/49页TechnicalTermsText上一页下一页机电专业英语徐存善主编physicalproperties物理性质atomicstructure原子结构nonferrousmetal有色金属small-lot小批量finishedproduct成品general-purpose普通用途special-purpose专用的，特殊用途的standardizedproduct【工程设计】标准化产品第14/49页LanguagepointsText上一页下一页机电专业英语徐存善主编1.Sincethereisaninfinitenumberofnonmetallicmaterialsaswellaspureandalloyedmetals,considerablestudyisnecessarytochoosetheappropriateone.译文：由于非金属材料与纯金属和合金的种类一样繁多，所以在选择合适的材料时需要做大量的研究工作。说明：句中aswellas和…一样，不但…而且；Sincethereisaninfinitenumberof…作原因状语从句。tochoosetheappropriateone作目的状语。considerable[kən'sidərəbl]adj.相当大的；重要的，值得考虑的1）relatedphrases：considerableorders大量订货；considerabledamage相当大损失2）Todrillthepropersizeholeinanexactlocationrequiresconsiderableskill.在准确的位置上钻一个尺寸正确的孔要求相当的技巧。3）Sheisawo