金属热处理外文及翻译

湖南工院毕业设计论文外文翻译外文题目HEATTREATMENTOFMETAL译文题目金属热处理系部机械工程系专业班级机械设计制造及其自动化学生姓名指导教师完成时间原文HEATTREATMENTOFMETALTHEGENERALLYACCEPTEDDEFINITIONFORHEATTREATINGMETALSANDMETALALLOYSIS“HEATINGANDCOOLINGASOLIDMETALORALLOYINAWAYSOASTOOBTAINSPECIFICCONDITIONSORPROPERTIES”HEATINGFORTHESOLEPURPOSEOFHOTWORKINGASINFORGINGOPERATIONSISEXCLUDEDFROMTHISDEFINITIONLIKEWISE，THETYPESOFHEATTREATMENTTHATARESOMETIMESUSEDFORPRODUCTSSUCHASGLASSORPLASTICSAREALSOEXCLUDEDFROMCOVERAGEBYTHISDEFINITIONTRANSFORMATIONCURVESTHEBASISFORHEATTREATMENTISTHETIMETEMPERATURETRANSFORMATIONCURVESORTTTCURVESWHERE，INASINGLEDIAGRAMALLTHETHREEPARAMETERSAREPLOTTEDBECAUSEOFTHESHAPEOFTHECURVES，THEYAREALSOSOMETIMESCALLEDCCURVESORSCURVESTOPLOTTTTCURVES，THEPARTICULARSTEELISHELDATAGIVENTEMPERATUREANDTHESTRUCTUREISEXAMINEDATPREDETERMINEDINTERVALSTORECORDTHEAMOUNTOFTRANSFORMATIONTAKENPLACEITISKNOWNTHATTHEEUTECTOIDSTEELT80UNDEREQUILIBRIUMCONDITIONSCONTAINS，ALLAUSTENITEABOVE723，WHEREASBELOW，ITISTHEPEARLITETOFORMPEARLITE，THECARBONATOMSSHOULDDIFFUSETOFORMCEMENTITETHEDIFFUSIONBEINGARATEPROCESS，WOULDREQUIRESUFFICIENTTIMEFORCOMPLETETRANSFORMATIONOFAUSTENITETOPEARLITEFROMDIFFERENTSAMPLES，ITISPOSSIBLETONOTETHEAMOUNTOFTHETRANSFORMATIONTAKINGPLACEATANYTEMPERATURETHESEPOINTSARETHENPLOTTEDONAGRAPHWITHTIMEANDTEMPERATUREASTHEAXESTHROUGHTHESEPOINTS，TRANSFORMATIONCURVESCANBEPLOTTEDASSHOWNINFIG1FOREUTECTOIDSTEELTHECURVEATEXTREMELEFTREPRESENTSTHETIMEREQUIREDFORTHETRANSFORMATIONOFAUSTENITETOPEARLITETOSTARTATANYGIVENTEMPERATURESIMILARLY，THECURVEATEXTREMERIGHTREPRESENTSTHETIMEREQUIREDFORCOMPLETINGTHETRANSFORMATIONBETWEENTHETWOCURVESARETHEPOINTSREPRESENTINGPARTIALTRANSFORMATIONTHEHORIZONTALLINESMSANDMFREPRESENTTHESTARTANDFINISHOFMARTENSITICTRANSFORMATIONCLASSIFICATIONOFHEATTREATINGPROCESSESINSOMEINSTANCES，HEATTREATMENTPROCEDURESARECLEARCUTINTERMSOFTECHNIQUEANDAPPLICATIONWHEREASINOTHERINSTANCES，DESCRIPTIONSORSIMPLEEXPLANATIONSAREINSUFFICIENTBECAUSETHESAMETECHNIQUEFREQUENTLYMAYBEUSEDTOOBTAINDIFFERENTOBJECTIVESFOREXAMPLE,STRESSRELIEVINGANDTEMPERINGAREOFTENACCOMPLISHEDWITHTHESAMEEQUIPMENTANDBYUSEOFIDENTICALTIMEANDTEMPERATURECYCLESTHEOBJECTIVES，HOWEVER，AREDIFFERENTFORTHETWOPROCESSESTHEFOLLOWINGDESCRIPTIONSOFTHEPRINCIPALHEATTREATINGPROCESSESAREGENERALLYARRANGEDACCORDINGTOTHEIRINTERRELATIONSHIPSNORMALIZINGCONSISTSOFHEATINGAFERROUSALLOYTOASUITABLETEMPERATUREUSUALLY50FTO100FOR28TO56ABOVEITSSPECIFICUPPERTRANSFORMATIONTEMPERATURETHISISFOLLOWEDBYCOOLINGINSTILLAIRTOATLEASTSOMETEMPERATUREWELLBELOWITSTRANSFORMATIONTEMPERATURERANGEFORLOWCARBONSTEELS,THERESULTINGSTRUCTUREANDPROPERTIESARETHESAMEASTHOSEACHIEVEDBYFULLANNEALING；FORMOSTFERROUSALLOYS,NORMALIZINGANDANNEALINGARENOTSYNONYMOUSNORMALIZINGUSUALLYISUSEDASACONDITIONINGTREATMENT,NOTABLYFORREFININGTHEGRAINSOFSTEELSTHATHAVEBEENSUBJECTEDTOHIGHTEMPERATURESFORFORGINGOROTHERHOTWORKINGOPERATIONSTHENORMALIZINGPROCESSUSUALLYISSUCCEEDEDBYANOTHERHEATTREATINGOPERATIONSUCHASAUSTENITIZINGFORHARDENING,ANNEALING,ORTEMPERINGANNEALINGISAGENERICTERMDENOTINGAHEATTREATMENTTHATCONSISTSOFHEATINGTOANDHOLDINGATASUITABLETEMPERATUREFOLLOWEDBYCOOLINGATASUITABLERATEITISUSEDPRIMARILYTOSOFTENMETALLICMATERIALS,BUTALSOTOSIMULTANEOUSLYPRODUCEDESIREDCHANGESINOTHERPROPERTIESORINMICROSTRUCTURETHEPURPOSEOFSUCHCHANGESMAYBE,BUTISNOTCONFINEDTO,IMPROVEMENTOFMACHINABILITY,FACILITATIONOFCOLDWORKKNOWNASINPROCESSANNEALING,IMPROVEMENTOFMECHANICALORELECTRICALPROPERTIES,ORTOINCREASEDIMENSIONALSTABILITYWHENAPPLIEDSOLELYTORELIVESTRESSES,ITCOMMONLYISCALLEDSTRESSRELIEFANNEALING,SYNONYMOUSWITHSTRESSRELIEVINGWHENTHETERM“ANNEALING”ISAPPLIEDTOFERROUSALLOYSWITHOUTQUALIFICATION,FULLANNEALINGISAPPLIEDTHISISACHIEVEDBYHEATINGABOVETHEALLOYSTRANSFORMATIONTEMPERATURE,THENAPPLYINGACOOLINGCYCLEWHICHPROVIDESMAXIMUMSOFTNESSTHISCYCLEMAYVARYWIDELY,DEPENDINGONCOMPOSITIONANDCHARACTERISTICSOFTHESPECIFICALLOYQUENCHINGISARAPIDCOOLINGOFASTEELORALLOYFROMTHEAUSTENITIZINGTEMPERATUREBYIMMERSINGTHEWORKPIECEINALIQUIDORGASEOUSMEDIUMQUENCHINGMEDIUMCOMMONLYUSEDINCLUDEWATER,5BRINE,5CAUSTICINANAQUEOUSSOLUTION,OIL,POLYMERSOLUTIONS,ORGASUSUALLYAIRORNITROGENSELECTIONOFAQUENCHINGMEDIUMDEPENDSLARGELYONTHEHARDENABILITYOFMATERIALANDTHEMASSOFTHEMATERIALBEINGTREATINGPRINCIPALLYSECTIONTHICKNESSTHECOOLINGCAPABILITIESOFTHEABOVELISTEDQUENCHINGMEDIAVARYGREATLYINSELECTINGAQUENCHINGMEDIUM,ITISBESTTOAVOIDASOLUTIONTHATHASMORECOOLINGPOWERTHANISNEEDEDTOACHIEVETHERESULTS,THUSMINIMIZINGTHEPOSSIBILITYOFCRACKINGANDWARPOFTHEPARTSBEINGTREATEDMODIFICATIONSOFTHETERMQUENCHINGINCLUDEDIRECTQUENCHING,FOGQUENCHING,HOTQUENCHING,INTERRUPTEDQUENCHING,SELECTIVEQUENCHING,SPRAYQUENCHING,ANDTIMEQUENCHINGTEMPERINGINHEATTREATINGOFFERROUSALLOYS,TEMPERINGCONSISTSOFREHEATINGTHEAUSTENITIZEDANDQUENCHHARDENEDSTEELORIRONTOSOMEPRESELECTEDTEMPERATURETHATISBELOWTHELOWERTRANSFORMATIONTEMPERATUREGENERALLYBELOW1300OR705TEMPERINGOFFERSAMEANSOFOBTAININGVARIOUSCOMBINATIONSOFMECHANICALPROPERTIESTEMPERINGTEMPERATURESUSEDFORHARDENEDSTEELSAREOFTENNOHIGHERTHAN300150THETERM“TEMPERING”SHOULDNOTBECONFUSEDWITHEITHERPROCESSANNEALINGORSTRESSRELIEVINGEVENTHOUGHTIMEANDTEMPERATURECYCLESFORTHETHREEPROCESSESMAYBETHESAME,THECONDITIONSOFTHEMATERIALSBEINGPROCESSEDANDTHEOBJECTIVESMAYBEDIFFERENTSTRESSRELIEVINGLIKETEMPERING,STRESSRELIEVINGISALWAYSDONEBYHEATINGTOSOMETEMPERATUREBELOWTHELOWERTRANSFORMATIONTEMPERATUREFORSTEELSANDIRONSFORNONFERROUSMETALS,THETEMPERATUREMAYVARYFROMSLIGHTLYABOVEROOMTEMPERATURETOSEVERALHUNDREDDEGREES,DEPENDINGONTHEALLOYANDTHEAMOUNTOFSTRESSRELIEFTHATISDESIREDTHEPRIMARYPURPOSEOFSTRESSRELIEVINGISTORELIEVESTRESSESTHATHAVEBEENIMPARTEDTOTHEWORKPIECEFROMSUCHPROCESSESASFORMING,ROLLING,MACHININGORWELDINGTHEUSUALPROCEDUREISTOHEATWORKPIECETOTHEPREESTABLISHEDTEMPERATURELONGENOUGHTOREDUCETHERESIDUALSTRESSESTHISISATIMEANDTEMPERATUREDEPENDENTOPERATIONTOANACCEPTABLELEVELTHISISFOLLOWEDBYCOOLINGATARELATIVELYSLOWRATETOAVOIDCREATIONOFNEWSTRESSESTHEGENERALLYACCEPTEDDEFINITIONFORHEATTREATINGMETALSANDMETALALLOYSIS“HEATINGANDCOOLINGASOLIDMETALORALLOYINAWAYSOASTOOBTAINSPECIFICCONDITIONSORPROPERTIES”HEATINGFORTHESOLEPURPOSEOFHOTWORKINGASINFORGINGOPERATIONSISEXCLUDEDFROMTHISDEFINITIONLIKEWISE，THETYPESOFHEATTREATMENTTHATARESOMETIMESUSEDFORPRODUCTSSUCHASGLASSORPLASTICSAREALSOEXCLUDEDFROMCOVERAGEBYTHISDEFINITIONTRANSFORMATIONCURVESTHEBASISFORHEATTREATMENTISTHETIMETEMPERATURETRANSFORMATIONCURVESORTTTCURVESWHERE，INASINGLEDIAGRAMALLTHETHREEPARAMETERSAREPLOTTEDBECAUSEOFTHESHAPEOFTHECURVES，THEYAREALSOSOMETIMESCALLEDCCURVESORSCURVESTOPLOTTTTCURVES，THEPARTICULARSTEELISHELDATAGIVENTEMPERATUREANDTHESTRUCTUREISEXAMINEDATPREDETERMINEDINTERVALSTORECORDTHEAMOUNTOFTRANSFORMATIONTAKENPLACEITISKNOWNTHATTHEEUTECTOIDSTEELT80UNDEREQUILIBRIUMCONDITIONSCONTAINS，ALLAUSTENITEABOVE723，WHEREASBELOW，ITISPEARLITETOFORMPEARLITE，THECARBONATOMSSHOULDDIFFUSETOFORMCEMENTITETHEDIFFUSIONBEINGARATEPROCESS，WOULDREQUIRESUFFICIENTTIMEFORCOMPLETETRANSFORMATIONOFAUSTENITETOPEARLITEFROMDIFFERENTSAMPLES，ITISPOSSIBLETONOTETHEAMOUNTOFTHETRANSFORMATIONTAKINGPLACEATANYTEMPERATURETHESEPOINTSARETHENPLOTTEDONAGRAPHWITHTIMEANDTEMPERATUREASTHEAXESTHROUGHTHESEPOINTS，TRANSFORMATIONCURVESCANBEPLOTTEDASSHOWNINFIG1FOREUTECTOIDSTEELTHECURVEATEXTREMELEFTREPRESENTSTHETIMEREQUIREDFORTHETRANSFORMATIONOFAUSTENITETOPEARLITETOSTARTATANYGIVENTEMPERATURESIMILARLY，THECURVEATEXTREMERIGHTREPRESENTSTHETIMEREQUIREDFORCOMPLETINGTHETRANSFORMATIONBETWEENTHETWOCURVESARETHEPOINTSREPRESENTINGPARTIALTRANSFORMATIONTHEHORIZONTALLINESMSANDMFREPRESENTTHESTARTANDFINISHOFMARTENSITICTRANSFORMATIONCLASSIFICATIONOFHEATTREATINGPROCESSESINSOMEINSTANCES，HEATTREATMENTPROCEDURESARECLEARCUTINTERMSOFTECHNIQUEANDAPPLICATIONWHEREASINOTHERINSTANCES，DESCRIPTIONSORSIMPLEEXPLANATIONSAREINSUFFICIENTBECAUSETHESAMETECHNIQUEFREQUENTLYMAYBEUSEDTOOBTAINDIFFERENTOBJECTIVESFOREXAMPLE,STRESSRELIEVINGANDTEMPERINGAREOFTENACCOMPLISHEDWITHTHESAMEEQUIPMENTANDBYUSEOFIDENTICALTIMEANDTEMPERATURECYCLESTHEOBJECTIVES，HOWEVER，AREDIFFERENTFORTHETWOPROCESSESTHEFOLLOWINGDESCRIPTIONSOFTHEPRINCIPALHEATTREATINGPROCESSESAREGENERALLYARRANGEDACCORDINGTOTHEIRINTERRELATIONSHIPSNORMALIZINGCONSISTSOFHEATINGAFERROUSALLOYTOASUITABLETEMPERATUREUSUALLY50FTO100FOR28TO56ABOVEITSSPECIFICUPPERTRANSFORMATIONTEMPERATURETHISISFOLLOWEDBYCOOLINGINSTILLAIRTOATLEASTSOMETEMPERATUREWELLBELOWITSTRANSFORMATIONTEMPERATURERANGEFORLOWCARBONSTEELS,THERESULTINGSTRUCTUREANDPROPERTIESARETHESAMEASTHOSEACHIEVEDBYFULLANNEALING；FORMOSTFERROUSALLOYS,NORMALIZINGANDANNEALINGARENOTSYNONYMOUSNORMALIZINGUSUALLYISUSEDASACONDITIONINGTREATMENT,NOTABLYFORREFININGTHEGRAINSOFSTEELSTHATHAVEBEENSUBJECTEDTOHIGHTEMPERATURESFORFORGINGOROTHERHOTWORKINGOPERATIONSTHENORMALIZINGPROCESSUSUALLYISSUCCEEDEDBYANOTHERHEATTREATINGOPERATIONSUCHASAUSTENITIZINGFORHARDENING,ANNEALING,ORTEMPERINGANNEALINGISAGENERICTERMDENOTINGAHEATTREATMENTTHATCONSISTSOFHEATINGTOANDHOLDINGATASUITABLETEMPERATUREFOLLOWEDBYCOOLINGATASUITABLERATEITISUSEDPRIMARILYTOSOFTENMETALLICMATERIALS,BUTALSOTOSIMULTANEOUSLYPRODUCEDESIREDCHANGESINOTHERPROPERTIESORINMICROSTRUCTURETHEPURPOSEOFSUCHCHANGESMAYBE,BUTISNOTCONFINEDTO,IMPROVEMENTOFMACHINABILITY,FACILITATIONOFCOLDWORKKNOWNASINPROCESSANNEALING,IMPROVEMENTOFMECHANICALORELECTRICALPROPERTIES,ORTOINCREASEDIMENSIONALSTABILITYWHENAPPLIEDSOLELYTORELIVESTRESSES,ITCOMMONLYISCALLEDSTRESSRELIEFANNEALING,SYNONYMOUSWITHSTRESSRELIEVINGWHENTHETERM“ANNEALING”ISAPPLIEDTOFERROUSALLOYSWITHOUTQUALIFICATION,FULLANNEALINGISAPPLIEDTHISISACHIEVEDBYHEATINGABOVETHEALLOYSTRANSFORMATIONTEMPERATURE,THENAPPLYINGACOOLINGCYCLEWHICHPROVIDESMAXIMUMSOFTNESSTHISCYCLEMAYVARYWIDELY,DEPENDINGONCOMPOSITIONANDCHARACTERISTICSOFTHESPECIFICALLOYQUENCHINGISARAPIDCOOLINGOFASTEELORALLOYFROMTHEAUSTENITIZINGTEMPERATUREBYIMMERSINGTHEWORKPIECEINALIQUIDORGASEOUSMEDIUMQUENCHINGMEDIUMCOMMONLYUSEDINCLUDEWATER,5BRINE,5CAUSTICINANAQUEOUSSOLUTION,OIL,POLYMERSOLUTIONS,ORGASUSUALLYAIRORNITROGENSELECTIONOFAQUENCHINGMEDIUMDEPENDSLARGELYONTHEHARDENABILITYOFMATERIALANDTHEMASSOFTHEMATERIALBEINGTREATINGPRINCIPALLYSECTIONTHICKNESSTHECOOLINGCAPABILITIESOFTHEABOVELISTEDQUENCHINGMEDIAVARYGREATLYINSELECTINGAQUENCHINGMEDIUM,ITISBESTTOAVOIDASOLUTIONTHATHASMORECOOLINGPOWERTHANISNEEDEDTOACHIEVETHERESULTS,THUSMINIMIZINGTHEPOSSIBILITYOFCRACKINGANDWARPOFTHEPARTSBEINGTREATEDMODIFICATIONSOFTHETERMQUENCHINGINCLUDEDIRECTQUENCHING,FOGQUENCHING,HOTQUENCHING,INTERRUPTEDQUENCHING,SELECTIVEQUENCHING,SPRAYQUENCHING,ANDTIMEQUENCHINGTEMPERINGINHEATTREATINGOFFERROUSALLOYS,TEMPERINGCONSISTSOFREHEATINGTHEAUSTENITIZEDANDQUENCHHARDENEDSTEELORIRONTOSOMEPRESELECTEDTEMPERATURETHATISBELOWTHELOWERTRANSFORMATIONTEMPERATUREGENERALLYBELOW1300OR705TEMPERINGOFFERSAMEANSOFOBTAININGVARIOUSCOMBINATIONSOFMECHANICALPROPERTIESTEMPERINGTEMPERATURESUSEDFORHARDENEDSTEELSAREOFTENNOHIGHERTHAN300150THETERM“TEMPERING”SHOULDNOTBECONFUSEDWITHEITHERPROCESSANNEALINGORSTRESSRELIEVINGEVENTHOUGHTIMEANDTEMPERATURECYCLESFORTHETHREEPROCESSESMAYBETHESAME,THECONDITIONSOFTHEMATERIALSBEINGPROCESSEDANDTHEOBJECTIVESMAYBEDIFFERENTSTRESSRELIEVINGLIKETEMPERING,STRESSRELIEVINGISALWAYSDONEBYHEATINGTOSOMETEMPERATUREBELOWTHELOWERTRANSFORMATIONTEMPERATUREFORSTEELSANDIRONSFORNONFERROUSMETALS,THETEMPERATUREMAYVARYFROMSLIGHTLYABOVEROOMTEMPERATURETOSEVERALHUNDREDDEGREES,DEPENDINGONTHEALLOYANDTHEAMOUNTOFSTRESSRELIEFTHATISDESIREDTHEPRIMARYPURPOSEOFSTRESSRELIEVINGISTORELIEVESTRESSESTHATHAVEBEENIMPARTEDTOTHEWORKPIECEFROMSUCHPROCESSESASFORMING,ROLLING,MACHININGORWELDINGTHEUSUALPROCEDUREISTOHEATWORKPIECETOTHEPREESTABLISHEDTEMPERATURELONGENOUGHTOREDUCETHERESIDUALSTRESSESTHISISATIMEANDTEMPERATUREDEPENDENTOPERATIONTOANACCEPTABLELEVELTHISISFOLLOWEDBYCOOLINGATARELATIVELYSLOWRATETOAVOIDCREATIONOFNEWSTRESSESTHEGENERALLYACCEPTEDDEFINITIONFORHEATTREATINGMETALSANDMETALALLOYSIS“HEATINGANDCOOLINGASOLIDMETALORALLOYINAWAYSOASTOOBTAINSPECIFICCONDITIONSORPROPERTIES”HEATINGFORTHESOLEPURPOSEOFHOTWORKINGASINFORGINGOPERATIONSISEXCLUDEDFROMTHISDEFINITIONLIKEWISE，THETYPESOFHEATTREATMENTTHATARESOMETIMESUSEDFORPRODUCTSSUCHASGLASSORPLASTICSAREALSOEXCLUDEDFROMCOVERAGEBYTHISDEFINITIONTRANSFORMATIONCURVESTHEBASISFORHEATTREATMENTISTHETIMETEMPERATURETRANSFORMATIONCURVESORTTTCURVESWHERE，INASINGLEDIAGRAMALLTHETHREEPARAMETERSAREPLOTTEDBECAUSEOFTHESHAPEOFTHECURVES，THEYAREALSOSOMETIMESCALLEDCCURVESORSCURVESTOPLOTTTTCURVES，THEPARTICULARSTEELISHELDATAGIVENTEMPERATUREANDTHESTRUCTUREISEXAMINEDATPREDETERMINEDINTERVALSTORECORDTHEAMOUNTOFTRANSFORMATIONTAKENPLACEITISKNOWNTHATTHEEUTECTOIDSTEELT80UNDEREQUILIBRIUMCONDITIONSCONTAINS，ALLAUSTENITEABOVE723，WHEREASBELOW，ITISPEARLITETOFORMPEARLITE，THECARBONATOMSSHOULDDIFFUSETOFORMCEMENTITETHEDIFFUSIONBEINGARATEPROCESS，WOULDREQUIRESUFFICIENTTIMEFORCOMPLETETRANSFORMATIONOFAUSTENITETOPEARLITEFROMDIFFERENTSAMPLES，ITISPOSSIBLETONOTETHEAMOUNTOFTHETRANSFORMATIONTAKINGPLACEATANYTEMPERATURETHESEPOINTSARETHENPLOTTEDONAGRAPHWITHTIMEANDTEMPERATUREASTHEAXESTHROUGHTHESEPOINTS，TRANSFORMATIONCURVESCANBEPLOTTEDASSHOWNINFIG1FOREUTECTOIDSTEELTHECURVEATEXTREMELEFTREPRESENTSTHETIMEREQUIREDFORTHETRANSFORMATIONOFAUSTENITETOPEARLITETOSTARTATANYGIVENTEMPERATURESIMILARLY，THECURVEATEXTREMERIGHTREPRESENTSTHETIMEREQUIREDFORCOMPLETINGTHETRANSFORMATIONBETWEENTHETWOCURVESARETHEPOINTSREPRESENTINGPARTIALTRANSFORMATIONTHEHORIZONTALLINESMSANDMFREPRESENTTHESTARTANDFINISHOFMARTENSITICTRANSFORMATIONCLASSIFICATIONOFHEATTREATINGPROCESSESINSOMEINSTANCES，HEATTREATMENTPROCEDURESARECLEARCUTINTERMSOFTECHNIQUEANDAPPLICATIONWHEREASINOTHERINSTANCES，DESCRIPTIONSORSIMPLEEXPLANATIONSAREINSUFFICIENTBECAUSETHESAMETECHNIQUEFREQUENTLYMAYBEUSEDTOOBTAINDIFFERENTOBJECTIVESFOREXAMPLE,STRESSRELIEVINGANDTEMPERINGAREOFTENACCOMPLISHEDWITHTHESAMEEQUIPMENTANDBYUSEOFIDENTICALTIMEANDTEMPERATURECYCLESTHEOBJECTIVES，HOWEVER，AREDIFFERENTFORTHETWOPROCESSESTHEFOLLOWINGDESCRIPTIONSOFTHEPRINCIPALHEATTREATINGPROCESSESAREGENERALLYARRANGEDACCORDINGTOTHEIRINTERRELATIONSHIPSNORMALIZINGCONSISTSOFHEATINGAFERROUSALLOYTOASUITABLETEMPERATUREUSUALLY50FTO100FOR28TO56ABOVEITSSPECIFICUPPERTRANSFORMATIONTEMPERATURETHISISFOLLOWEDBYCOOLINGINSTILLAIRTOATLEASTSOMETEMPERATUREWELLBELOWITSTRANSFORMATIONTEMPERATURERANGEFORLOWCARBONSTEELS,THERESULTINGSTRUCTUREANDPROPERTIESARETHESAMEASTHOSEACHIEVEDBYFULLANNEALING；FORMOSTFERROUSALLOYS,NORMALIZINGANDANNEALINGARENOTSYNONYMOUSNORMALIZINGUSUALLYISUSEDASACONDITIONINGTREATMENT,NOTABLYFORREFININGTHEGRAINSOFSTEELSTHATHAVEBEENSUBJECTEDTOHIGHTEMPERATURESFORFORGINGOROTHERHOTWORKINGOPERATIONSTHENORMALIZINGPROCESSUSUALLYISSUCCEEDEDBYANOTHERHEATTREATINGOPERATIONSUCHASAUSTENITIZINGFORHARDENING,ANNEALING,ORTEMPERINGANNEALINGISAGENERICTERMDENOTINGAHEATTREATMENTTHATCONSISTSOFHEATINGTOANDHOLDINGATASUITABLETEMPERATUREFOLLOWEDBYCOOLINGATASUITABLERATEITISUSEDPRIMARILYTOSOFTENMETALLICMATERIALS,BUTALSOTOSIMULTANEOUSLYPRODUCEDESIREDCHANGESINOTHERPROPERTIESORINMICROSTRUCTURETHEPURPOSEOFSUCHCHANGESMAYBE,BUTISNOTCONFINEDTO,IMPROVEMENTOFMACHINABILITY,FACILITATIONOFCOLDWORKKNOWNASINPROCESSANNEALING,IMPROVEMENTOFMECHANICALORELECTRICALPROPERTIES,ORTOINCREASEDIMENSIONALSTABILITYWHENAPPLIEDSOLELYTORELIVESTRESSES,ITCOMMONLYISCALLEDSTRESSRELIEFANNEALING,SYNONYMOUSWITHSTRESSRELIEVINGWHENTHETERM“ANNEALING”ISAPPLIEDTOFERROUSALLOYSWITHOUTQUALIFICATION,FULLANNEALINGISAPPLIEDTHISISACHIEVEDBYHEATINGABOVETHEALLOYSTRANSFORMATIONTEMPERATURE,THENAPPLYINGACOOLINGCYCLEWHICHPROVIDESMAXIMUMSOFTNESSTHISCYCLEMAYVARYWIDELY,DEPENDINGONCOMPOSITIONANDCHARACTERISTICSOFTHESPECIFICALLOYQUENCHINGISARAPIDCOOLINGOFASTEELORALLOYFROMTHEAUSTENITIZINGTEMPERATUREBYIMMERSINGTHEWORKPIECEINALIQUIDORGASEOUSMEDIUMQUENCHINGMEDIUMCOMMONLYUSEDINCLUDEWATER,5BRINE,5CAUSTICINANAQUEOUSSOLUTION,OIL,POLYMERSOLUTIONS,ORGASUSUALLYAIRORNITROGENSELECTIONOFAQUENCHINGMEDIUMDEPENDSLARGELYONTHEHARDENABILITYOFMATERIALANDTHEMASSOFTHEMATERIALBEINGTREATINGPRINCIPALLYSECTIONTHICKNESSTHECOOLINGCAPABILITIESOFTHEABOVELISTEDQUENCHINGMEDIAVARYGREATLYINSELECTINGAQUENCHINGMEDIUM,ITISBESTTOAVOIDASOLUTIONTHATHASMORECOOLINGPOWERTHANISNEEDEDTOACHIEVETHERESULTS,THUSMINIMIZINGTHEPOSSIBILITYOFCRACKINGANDWARPOFTHEPARTSBEINGTREATEDMODIFICATIONSOFTHETERMQUENCHINGINCLUDEDIRECTQUENCHING,FOGQUENCHING,HOTQUENCHING,INTERRUPTEDQUENCHING,SELECTIVEQUENCHING,SPRAYQUENCHING,ANDTIMEQUENCHINGTEMPERINGINHEATTREATINGOFFERROUSALLOYS,TEMPERINGCONSISTSOFREHEATINGTHEAUSTENITIZEDANDQUENCHHARDENEDSTEELORIRONTOSOMEPRESELECTEDTEMPERATURETHATISBELOWTHELOWERTRANSFORMATIONTEMPERATUREGENERALLYBELOW1300OR705TEMPERINGOFFERSAMEANSOFOBTAININGVARIOUSCOMBINATIONSOFMECHANICALPROPERTIESTEMPERINGTEMPERATURESUSEDFORHARDENEDSTEELSAREOFTENNOHIGHERTHAN300OF150THETERM“TEMPERING”SHOULDNOTBECONFUSEDWITHEITHERPROCESSANNEALINGORSTRESSRELIEVINGEVENTHOUGHTIMEANDTEMPERATURECYCLESFORTHETHREEPROCESSESMAYBETHESAME,THECONDITIONSOFTHEMATERIALSBEINGPROCESSEDANDTHEOBJECTIVESMAYBEDIFFERENTSTRESSRELIEVINGLIKETEMPERING,STRESSRELIEVINGISALWAYSDONEBYHEATINGTOSOMETEMPERATUREBELOWTHELOWERTRANSFORMATIONTEMPERATUREFORSTEELSANDIRONSFORNONFERROUSMETALS,THETEMPERATUREMAYVARYFROMSLIGHTLYABOVEROOMTEMPERATURETOSEVERALHUNDREDDEGREES,DEPENDINGONTHEALLOYANDTHEAMOUNTOFSTRESSRELIEFTHATISDESIREDTHEPRIMARYPURPOSEOFSTRESSRELIEVINGISTORELIEVESTRESSESTHATHAVEBEENIMPARTEDTOTHEWORKPIECEFROMSUCHPROCESSESASFORMING,ROLLING,MACHININGORWELDINGTHEUSUALPROCEDUREISTOHEATWORKPIECETOTHEPREEST