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外文译文院（系）机电工程学院专业机械设计制造及其自动化姓名学号ZJD02043指导教师评语签名年月日外语文献翻译摘自制造工程与技术（机加工）（英文版）MANUFACTURINGENGINEERINGANDTECHNOLOGYMACHINING机械工业出版社2004年3月第1版页564560P美S卡尔帕基安SEROPEKALPAKJIANSR施密德STEVENRSCHMID著原文209MACHINABILITYTHEMACHINABILITYOFAMATERIALUSUALLYDEFINEDINTERMSOFFOURFACTORS1、SURFACEFINISHANDINTEGRITYOFTHEMACHINEDPART；2、TOOLLIFEOBTAINED；3、FORCEANDPOWERREQUIREMENTS；4、CHIPCONTROLTHUS,GOODMACHINABILITYGOODSURFACEFINISHANDINTEGRITY,LONGTOOLLIFE,ANDLOWFORCEANDPOWERREQUIREMENTSASFORCHIPCONTROL,LONGANDTHINSTRINGYCUREDCHIPS,IFNOTBROKENUP,CANSEVERELYINTERFEREWITHTHECUTTINGOPERATIONBYBECOMINGENTANGLEDINTHECUTTINGZONEBECAUSEOFTHECOMPLEXNATUREOFCUTTINGOPERATIONS,ITISDIFFICULTTOESTABLISHRELATIONSHIPSTHATQUANTITATIVELYDEFINETHEMACHINABILITYOFAMATERIALINMANUFACTURINGPLANTS,TOOLLIFEANDSURFACEROUGHNESSAREGENERALLYCONSIDEREDTOBETHEMOSTIMPORTANTFACTORSINMACHINABILITYALTHOUGHNOTUSEDMUCHANYMORE,APPROXIMATEMACHINABILITYRATINGSAREAVAILABLEINTHEEXAMPLEBELOW2091MACHINABILITYOFSTEELSBECAUSESTEELSAREAMONGTHEMOSTIMPORTANTENGINEERINGMATERIALSASNOTEDINCHAPTER5,THEIRMACHINABILITYHASBEENSTUDIEDEXTENSIVELYTHEMACHINABILITYOFSTEELSHASBEENMAINLYIMPROVEDBYADDINGLEADANDSULFURTOOBTAINSOCALLEDFREEMACHININGSTEELSRESULFURIZEDANDREPHOSPHORIZEDSTEELSSULFURINSTEELSFORMSMANGANESESULFIDEINCLUSIONSSECONDPHASEPARTICLES,WHICHACTASSTRESSRAISERSINTHEPRIMARYSHEARZONEASARESULT,THECHIPSPRODUCEDBREAKUPEASILYANDARESMALL；THISIMPROVESMACHINABILITYTHESIZE,SHAPE,DISTRIBUTION,ANDCONCENTRATIONOFTHESEINCLUSIONSSIGNIFICANTLYINFLUENCEMACHINABILITYELEMENTSSUCHASTELLURIUMANDSELENIUM,WHICHAREBOTHCHEMICALLYSIMILARTOSULFUR,ACTASINCLUSIONMODIFIERSINRESULFURIZEDSTEELSPHOSPHORUSINSTEELSHASTWOMAJOREFFECTSITSTRENGTHENSTHEFERRITE,CAUSINGINCREASEDHARDNESSHARDERSTEELSRESULTINBETTERCHIPFORMATIONANDSURFACEFINISHNOTETHATSOFTSTEELSCANBEDIFFICULTTOMACHINE,WITHBUILTUPEDGEFORMATIONANDPOORSURFACEFINISHTHESECONDEFFECTISTHATINCREASEDHARDNESSCAUSESTHEFORMATIONOFSHORTCHIPSINSTEADOFCONTINUOUSSTRINGYONES,THEREBYIMPROVINGMACHINABILITYLEADEDSTEELSAHIGHPERCENTAGEOFLEADINSTEELSSOLIDIFIESATTHETIPOFMANGANESESULFIDEINCLUSIONSINNONRESULFURIZEDGRADESOFSTEEL,LEADTAKESTHEFORMOFDISPERSEDFINEPARTICLESLEADISINSOLUBLEINIRON,COPPER,ANDALUMINUMANDTHEIRALLOYSBECAUSEOFITSLOWSHEARSTRENGTH,THEREFORE,LEADACTSASASOLIDLUBRICANTSECTION3211ANDISSMEAREDOVERTHETOOLCHIPINTERFACEDURINGCUTTINGTHISBEHAVIORHASBEENVERIFIEDBYTHEPRESENCEOFHIGHCONCENTRATIONSOFLEADONTHETOOLSIDEFACEOFCHIPSWHENMACHININGLEADEDSTEELSWHENTHETEMPERATUREISSUFFICIENTLYHIGHFORINSTANCE,ATHIGHCUTTINGSPEEDSANDFEEDSSECTION206THELEADMELTSDIRECTLYINFRONTOFTHETOOL,ACTINGASALIQUIDLUBRICANTINADDITIONTOTHISEFFECT,LEADLOWERSTHESHEARSTRESSINTHEPRIMARYSHEARZONE,REDUCINGCUTTINGFORCESANDPOWERCONSUMPTIONLEADCANBEUSEDINEVERYGRADEOFSTEEL,SUCHAS10XX,11XX,12XX,41XX,ETCLEADEDSTEELSAREIDENTIFIEDBYTHELETTERLBETWEENTHESECONDANDTHIRDNUMERALSFOREXAMPLE,10L45NOTETHATINSTAINLESSSTEELS,SIMILARUSEOFTHELETTERLMEANS“LOWCARBON,”ACONDITIONTHATIMPROVESTHEIRCORROSIONRESISTANCEHOWEVER,BECAUSELEADISAWELLKNOWNTOXINANDAPOLLUTANT,THEREARESERIOUSENVIRONMENTALCONCERNSABOUTITSUSEINSTEELSESTIMATEDAT4500TONSOFLEADCONSUMPTIONEVERYYEARINTHEPRODUCTIONOFSTEELSCONSEQUENTLY,THEREISACONTINUINGTRENDTOWARDELIMINATINGTHEUSEOFLEADINSTEELSLEADFREESTEELSBISMUTHANDTINARENOWBEINGINVESTIGATEDASPOSSIBLESUBSTITUTESFORLEADINSTEELSCALCIUMDEOXIDIZEDSTEELSANIMPORTANTDEVELOPMENTISCALCIUMDEOXIDIZEDSTEELS,INWHICHOXIDEFLAKESOFCALCIUMSILICATESCASOAREFORMEDTHESEFLAKES,INTURN,REDUCETHESTRENGTHOFTHESECONDARYSHEARZONE,DECREASINGTOOLCHIPINTERFACEANDWEARTEMPERATUREISCORRESPONDINGLYREDUCEDCONSEQUENTLY,THESESTEELSPRODUCELESSCRATERWEAR,ESPECIALLYATHIGHCUTTINGSPEEDSSTAINLESSSTEELSAUSTENITIC300SERIESSTEELSAREGENERALLYDIFFICULTTOMACHINECHATTERCANBESPROBLEM,NECESSITATINGMACHINETOOLSWITHHIGHSTIFFNESSHOWEVER,FERRITICSTAINLESSSTEELSALSO300SERIESHAVEGOODMACHINABILITYMARTENSITIC400SERIESSTEELSAREABRASIVE,TENDTOFORMABUILTUPEDGE,ANDREQUIRETOOLMATERIALSWITHHIGHHOTHARDNESSANDCRATERWEARRESISTANCEPRECIPITATIONHARDENINGSTAINLESSSTEELSARESTRONGANDABRASIVE,REQUIRINGHARDANDABRASIONRESISTANTTOOLMATERIALSTHEEFFECTSOFOTHERELEMENTSINSTEELSONMACHINABILITYTHEPRESENCEOFALUMINUMANDSILICONINSTEELSISALWAYSHARMFULBECAUSETHESEELEMENTSCOMBINEWITHOXYGENTOFORMALUMINUMOXIDEANDSILICATES,WHICHAREHARDANDABRASIVETHESECOMPOUNDSINCREASETOOLWEARANDREDUCEMACHINABILITYITISESSENTIALTOPRODUCEANDUSECLEANSTEELSCARBONANDMANGANESEHAVEVARIOUSEFFECTSONTHEMACHINABILITYOFSTEELS,DEPENDINGONTHEIRCOMPOSITIONPLAINLOWCARBONSTEELSLESSTHAN015CCANPRODUCEPOORSURFACEFINISHBYFORMINGABUILTUPEDGECASTSTEELSAREMOREABRASIVE,ALTHOUGHTHEIRMACHINABILITYISSIMILARTOTHATOFWROUGHTSTEELSTOOLANDDIESTEELSAREVERYDIFFICULTTOMACHINEANDUSUALLYREQUIREANNEALINGPRIORTOMACHININGMACHINABILITYOFMOSTSTEELSISIMPROVEDBYCOLDWORKING,WHICHHARDENSTHEMATERIALANDREDUCESTHETENDENCYFORBUILTUPEDGEFORMATIONOTHERALLOYINGELEMENTS,SUCHASNICKEL,CHROMIUM,MOLYBDENUM,ANDVANADIUM,WHICHIMPROVETHEPROPERTIESOFSTEELS,GENERALLYREDUCEMACHINABILITYTHEEFFECTOFBORONISNEGLIGIBLEGASEOUSELEMENTSSUCHASHYDROGENANDNITROGENCANHAVEPARTICULARLYDETRIMENTALEFFECTSONTHEPROPERTIESOFSTEELOXYGENHASBEENSHOWNTOHAVEASTRONGEFFECTONTHEASPECTRATIOOFTHEMANGANESESULFIDEINCLUSIONS；THEHIGHERTHEOXYGENCONTENT,THELOWERTHEASPECTRATIOANDTHEHIGHERTHEMACHINABILITYINSELECTINGVARIOUSELEMENTSTOIMPROVEMACHINABILITY,WESHOULDCONSIDERTHEPOSSIBLEDETRIMENTALEFFECTSOFTHESEELEMENTSONTHEPROPERTIESANDSTRENGTHOFTHEMACHINEDPARTINSERVICEATELEVATEDTEMPERATURES,FOREXAMPLE,LEADCAUSESEMBRITTLEMENTOFSTEELSLIQUIDMETALEMBRITTLEMENT,HOTSHORTNESS；SEESECTION143,ALTHOUGHATROOMTEMPERATUREITHASNOEFFECTONMECHANICALPROPERTIESSULFURCANSEVERELYREDUCETHEHOTWORKABILITYOFSTEELS,BECAUSEOFTHEFORMATIONOFIRONSULFIDE,UNLESSSUFFICIENTMANGANESEISPRESENTTOPREVENTSUCHFORMATIONATROOMTEMPERATURE,THEMECHANICALPROPERTIESOFRESULFURIZEDSTEELSDEPENDONTHEORIENTATIONOFTHEDEFORMEDMANGANESESULFIDEINCLUSIONSANISOTROPYREPHOSPHORIZEDSTEELSARESIGNIFICANTLYLESSDUCTILE,ANDAREPRODUCEDSOLELYTOIMPROVEMACHINABILITY
