模具专业英语图解教程李东君课件 7

Properselectionofthediematerialandofthediemanufacturingtechniquedetermines,toalargeextent,theusefullifeofformingdies.Diesmayhavetobereplacedforanumberofreasons,suchaschangesindimensionsduetowearorplasticdeformation,deteriorationofthesurfacefinish,breakdownoflubrication,andcrackingorbreakage.①Inhotimpressiondieforging,theprincipalmodesofdiefailureareerosion,thermalfatigue,mechanicalfatigueandpermanentplasticdeformation.TASK7.1Inerosion,alsocommonlycalleddiewear,materialisactuallyremovedfromthediesurfacebypressureandslidingofthedeformingmaterial,wearresistanceofthediematerial,diesurfacetemperature,relativeslidingspeedatthedieandmaterialinterfaceandthenatureoftheinterfacelayerarethemostsignificantfactorsinfluencingabrasivediewear.(1)Variablerelatedtotheprocessitself,includingfactorssuchassizeofthediecavity,typeofmachineused,deformationspeed,initialstocksize,temperaturetobeused,lubrication,productionrateandnumberofpartstobeproduced.④(2)Variablerelatedtothetypeofdieloading,includingspeedofloading,i.e.,impactorgradualcontacttimebetweendiesanddeformingmetal(thiscontacttimeisespeciallyimportantinhotforming),maximumloadandpressureonthedies,maximumandminimumdietemperatures,andnumberofloadingcyclestowhichthedieswillbesubjected.(3)Mechanicalpropertiesofthediematerial,includinghardenability,impactstrength,hotstrength(ifhotformingisconsidered)andresistancetothermalandmechanicalfatigue.Notes1、Diesmayhavetobereplacedforanumberofreasons,suchaschangesindimensionsduetowearorplasticdeformation,deteriorationofthesurfacefinish,breakdownoflubrication,andcrackingorbreakage.模具的更换是有很多种理由的，例如：由于磨损或塑性变形造成的尺寸变化，成型表面的腐蚀退化，润滑油作用的损坏，以及开裂和细纹损坏。Notes2、Diebreakageorcrackingisduetomechanicalfatigueandoccursincaseswherethediesareoverloadedandlocalstressesarehigh.

模具的开裂和细纹损坏是由于机械疲劳造成的，这种开裂和细纹损坏在模具过载和局部应力过高的情况下发生。“isdueto”和“occurs”是“Diebreakageorcracking”的两个谓语动词。“wherethediesareoverloadedandlocalstressesarehigh”是“cases”定语从句。Notes3、Dielifeanddiefailurearegreatlyaffectedbythemechanicalpropertiesofthediematerialsundertheconditionsthatexistinagivendeformationprocess.

模具的使用寿命和模具的失效极大程度地要受到模具材料在已给定的成型加工工艺条件下所表现出的机械性能的影响。“thatexistinagivendeformationprocess”是“conditions”的定语从句。Notes4、Variablerelatedtotheprocessitself,includingfactorssuchassizeofthediecavity,typeofmachineused,deformationspeed,initialstocksize,temperaturetobeused,lubrication,productionrateandnumberofpartstobeproduced.

与工艺本身相关的变量，包括模具型腔的尺寸，所采用的机床型号，变形速度，毛坯的初始尺寸，加工时的温度，润滑条件，生产率和零件批量。Theprocessofmetalformingisalwaysaccompaniedbyheatgeneration.Thisheatduetoplasticdeformationandthefrictionoftheinterfaceresultsinacomplexandchangingtemperaturefield.①Topredictthetemperaturefieldduringtheforgingprocessesisveryimportantsinceitinfluencesthelubricationconditions,thematerialbehaviorduringdeformation,thequalityoffinishedpartsandtheservicelifeofthedie.TASK7.2Theservicelifeofthedieisrestrictedbywear,thermalcrackingandfatigue,andplasticdeformation,etc.Therehavebeenmanyresearchprojectstoinvestigatetheinfluenceofthesefactorsontoollife.Ingeneral,however,thesurfacehardnessofthediedecreaseswhenthetemperatureofthedieincreasesduringrepeatedoperations,whichinducesthermalsofteningwarmforgingprocesses.Thethermalsofteningacceleratesthewear,thermalcrackingandfatigue,andtheplasticdeformationofthedie.Notes1、Thisheatduetoplasticdeformationandthefrictionoftheinterfaceresultsinacomplexandchangingtemperaturefield.源于塑性变形的热量和界面间的摩擦导致产生了一个既复杂又不断变化的温度场。本句有两个主语，分别是“thisheat”和“thefriction”；“duetoplasticdeformation”是形容词短语作“thisheat”的后置定语，“oftheinterface”是介词短语作“thefriction”的后置定语。Notes2、Therolesoflubricantsaretoreducefrictionbetweenthedieandtheworkpieceandtoreduceheat-transferfromthebillettothedieduringtheformingprocesses.

润滑的作用在于减少在成型加工过程中模具和工件间的摩擦以及钢坯向模具的热传递。本句“toredu