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第一课（第9页）2.汉翻英1.机械工业用于制造产品的材料，可以分为金属材料、聚合物、陶瓷和复合材料。Thematerialsusedformanufacturingproductscanbedividedintofourcategories:metallics,polymerics,ceramicsandcomposites.2.金属可以分为有色金属和黑色金属。Metallicscanbeclassifiedintonon-ferrousandferrousmetallics.3.塑料可以分为热固性塑料和热塑性塑料。Plasticscabbegroupedintothermosets(thermosettingplastics)andthermoplastics.4.复合材料可以由两种或两种以上性质不同的材料组合，保留各自的特点，得到单一材料无法比拟的、优越的综合性能。Acompositeconsistsoftwomorekindsofdifferentmaterials,witheachmaterialkeepingitsownproperty,togetthesuperiorsynthetical(combined)performancewhichisunparalled(unmatched)bythatoftheindividualmaterial.5.当其所处的工作环境变化时，智能材料能改变其性能、颜色和形状等。Anintelligentmaterialcanchangeitsproperty,color,shapeandsoonwhenitsworkingenvironmentchanges.第二课（第17页）2.汉翻英1.材料的特性可分为物理特性和化学特性两大类。Thepropertiesofamaterialcanbedividedintotwomaingroups:physicalandchemicalproperty.2.塑性材料在拉伸载荷的作用下应力达到屈服强度时，产生塑性变形。Whenthestressofamaterialundertheactionoftensileloadreachesyieldstrength,itwillproduceplasticdeformation.3.除软钢等材料有明显的屈服点外，合金钢和有色合金等塑性材料无明显的屈服点。Exceptthatmaterialssuchasmildsteelhaveobviousyieldingpoint,plasticmaterialssuchasalloysteelandnon-ferrousalloyshavenoobviousyieldingpoint.4.脆性材料拉伸时，以抗拉强度为极限应力，压缩时以抗压强度为极限应力。Whenabrittlematerialisstretched,thetensilestrengthisusedasitsultimatestress,andwhenthematerialiscompressed,compressivestrengthisusedasitsultimatestress.5.蠕变是指材料在恒定温度和恒定应力的长期作用下，随着时间的延长会缓慢的发生塑性变形的现象。Creepisreferredtothephenomenathatunderthelong-timeactionofconstanttemperatureandload,thematerialwillslowlyproduceplasticdeformationwiththeextensionoftime.第五课（第39页）2.汉翻英1.将金属从矿石中分离出来的过程叫冶炼。Theprocessinwhichmetalisseparatedfromoreiscalledsmelting.2.几乎所有的黑色金属中都含有碳。Almostalltheferrousmetallicscontaincarbon.3.影响铸件质量的因素很多。Thefactorsthataffectthequalityofacastingarenumerous.4.通常认为金属铸造是艺术与科学的结合。Itisusuallybelievedthatmetalcastingisacombinationofartandscience.5.熔模铸造具有很多独特的优点。Investmentcastinghasmanypeculiaradvantages.第六课（第45页）2.汉翻英1.今天，在锻造工艺中，金属的成形并非总是采用加热和锻打的方法。Today，inforgingprocess,metalformingdoesnotalwaysusethemethodofheatingandhammering.2.液压机锻锤被广泛地用于锻造工艺中。Hydraulicpressesandthehammerarewidelyusedinforgingprocess.3.随着锻造技术的进步，许多以前认为不可能锻的材料现在也可通过常规锻造工艺进行加工。Withthedevelopmentofforgingtechnology,manymaterialswhichwasbelievedthatitwasimpossibletobeforgedcannowbeforgedwiththeregularforgingprocess.4.锻造就是要使金属材料变形为所需要的形状，而不同的材料对外界所施加的变形力的反应极不相同。Thepurposeofforgingistomaketheshapeofmetaltobechangedintowhatisneeded,andtheresponsesofdifferentmaterialstothedeformingforceexertedbyoutsidesareextremelydifferent.5.锻造设备的行为是锻造技术发展的一个重要课题，因为它直接影响着锻造工艺的效果。Thebehaviorofforgingequipmentsisanimportanttopicinthedevelopmentofforgingtechnology,becauseitdirectlyinfluencestheeffectsofforgingprocess.第九课2．汉翻英1．螺杆用来传递运动和力。Screwthreadsareusedtotransmitmotionandforce.2.铆接既可以是搭接也可以是对接。Rivetjointscanbeeitheralaporabuttjoint.3.焊接残余应力是由于热膨胀和收缩不均匀产生的。Weldingresidualstressisproducedbytheuneventhermalexpansionorcontraction4.在焊接设计时，要考虑安全因素。Safetyfactorsshouldbeconsideredinweldingdesign.5.胶接连接的强度取决于树脂对金属表面的粘附力和树脂本身分子之间的结合力。Thestrengthofadhesivejointisdeterminedbytheadhesionoftheresintothemetalsurfaces,andthecohesionbetweenthemoleculesoftheresinitself.第十课2．汉翻英1．带传动和链传动联接两个或多个轴来传递旋转运动和运动。Beltandchainareusedtoconnecttwoormoreshaftsfortransmissionofrotationandpower.2.链传动的传动比计算跟齿轮的传动一样，即与齿数成反比。Thespeedratioofachaindriveisthesameasthatofageardrive,namely,theinverseratioofthetoothnumber.3.链长必须是节距即一个连节的长度的倍数，节距的数目最好是偶数。Thechainlengthmustbeamultipleofthelengthofoneshackleanditispreferablethatthenumberofpitchesiseven.4.行星轮系在较小的空间内能得到较大的传动比。Planetarygeartrainscangetlargerspeedratioinasmallpackage.5.凸轮机构能把旋转运动转换成直线运动或摆动。Cammechanismcanconvertrotarymotionintolinearoroscillating(angular)motion.第十三棵2.汉译英1）液压系统有动力源、执行原件、控制元件和辅助系统组成。Ahydraulicsystemconsistsofpowersource,actuators,controldevicesandauxiliarysystem.2）根据动力源的不同，液压系统可分为恒流系统和恒压系统。Dependingonthepowerresource,ahydraulicsystemcanbedividedintoaconstantflowsystemandaconstantpressuresystem.3)齿轮泵是容积泵种结构最简单但效率最高的一种泵。Agearpumpisthesimplestinconfigurationandthemostefficientpumpofpositivedisplacementpump.4)液压系统中另一种重要元件是阀，主要有三种类型的阀：溢流阀、流量控制阀和方向控制阀。Anotherimportantdeviceinhydraulicsystemisvalve.Therearemainlythreetypesofvalve:reliefvalve,flowcontrolvalveanddirectioncontrolvalve.Lesson14Page1002.translatethefollowingsentencesintoEnglish:1)在车床加工中，工件的旋转为主运动，刀具的运动为进给运动。Inturningmachining,theturningofthework-pieceisprimarymotionandthemotionofthetoolisfeedmotion.2)常用的铣床有以下几种：1）立式铣床；2）卧式铣床；3）龙门铣床。Thecommonlyusedmillingmachinesareasthefollowingkinds:1)Horizontalmillingmachine;2)Verticalmillingmachines;3)Plano-millers。3）磨床加工形成的切屑非常小，以至难于与粉尘相区别。Chipsformedbyagrindingmachinearesosmallthatitisdifficulttotellthedifferencebetweenthemanddusts.4)机械加工在工业生产中得到了非常广泛的应用，它可以改变零件的几何形状，从而得到所需要的尺寸和表面质量。Machiningarewidelyusedinindustryproduction。Itcanchangethegeometricconfigurationofawork-pieceandformthedesiredsizeandsurfacequality。age119第17课2.汉译英1）电化学加工是一种电解过程，依靠电解池作为阴极和工件作为阳极发生电化学分解去除金属。ECM(electrochemicalmachining)isaelectrolyticprocess,inwhichmetalsareremovedbymeansofelectrochemicaldecompositi