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Whydon’tlowcarbonsteelsrepondtoquenching?Abstract:notbecauseoflowcarbonsteelquenchingcannotbefullyofmartensite,cannotachievegoodimprovethehardnessofthesteelandwearresistance.Soinactualproduction,notwidelyapplication.Keywords:low-carbonsteel,quenching,Martensite,hardness,wearresistanceLowcarbonsteelisqualityscorelessthan0.3%ofthesteelgrades,belongstothehypoeutectoidsteel.hypoeutectoidsteel,suitablefortheheatingtemperatureisabove30to50℃Ac3,afterquenchingcanobtainmartensiticorganizationoftinyevenly.Butbecauseofcarboncontentisinsufficient,soafterquenching,theorganizationwillappearferrite,causehardnessisinsufficient,thedecreaseofstrength.Thesteelquenchingisheatedtoadefinitetemperature,heatpreservationappropriatetimetoobtaincorrespondinghightemperaturephase,andthenrapidlycooling,togetawayfromtheequilibriumintheunstableheattreatmentprocessoftheorganization.Lowcarbonsteelquenchingcanformduplexsteel.Inrecentyears,withlow-alloysteeldevelopment,obviouslyimprovingthestrengthofthecomponent.But,thesekindsoflowcarbonsteelgeneraluse,alongwiththeincreaseofthecarboncontentofsteel,duplexsteelstrength,elongationincreaseddecline,willworsenduplexsteelcomponentsofformingperformance.参考文献【1】马永杰《热处理工艺600种》化学工业出版社【2】赵程杨建民《机械工程材料》机械工业出版社【3】樊东黎徐跃明《热处理工程师手册\》机械工业出版社AnAnalysisoftheEquilibriumDiagramoftheIronCarbonMetalAlloyAbstract:Ironcarbonalloyphasediagramofheattreatmentresearchisespeciallyimportant.Isfire,annealing,quenchingandtempering.Arethealloyphasetheironcarbon,accordingtothespecialsituationandbenchmarkdeterminetreatmenttemperature,holdingtimeandheattreatmentmethod.Theironcarbonalloy,tostudyvariouselementsonthebenchmarkofphasediagramofinfluenceisverymeaningful.Keywords:Ironcarbonalloyphasediagram，equilibrium，thermaltreatmentSteeliscertainingredientsrangeofironalloycarbon.Theliquidsteelinclosetoastateofbalanceslowcooling,solidificationthroughheattreatmentoftheformationofthemicrostructure,byoneorseveralstructureandcompositionoftheuniformphasecomposition.Theiron,carbonsteelandotherelementsinthesephaseinvariouswaystobetogether.Inironalloy,ironandcarboncarboncanformFe3C,Fe2C,FeCandaseriesofcompounds,andstablecompoundscanbeusedasanindependentunit.Therefore,thegeneralsaidironcarbonalloy,isactuallyreferstofigureiron-cementite(Fe-Fe3C)phasediagram,asshowninfigure.Ferriteisthestructuralformofpureironatroomtemperature.Ferriteissoftandductile.Ithasabodycentredcubicstructure,theinteratomicspacesaresmallandpronouncedlyoblate,andcannotreadilyaccommodateevenasmallcarbonatom.Themaximumsolubilityofcarboninferriteis0.0218%at727℃，theleastcarboncontentinferriteisalmostzeroatroomtemperature.Austeniteisthefacecentredmodificationofiron.Itisthestableformofpureironattemperaturesbetween910℃and1400℃.Atitsstabletemperatureausteniteissoftandductileandconsequently,iswellsuitedformanufacturingprocesses.Thefacecentredcubicstructureofironhaslargerinter-atomicspacingthaninferrite.Themaximumsolubilityis2.11%ofcarbonat1148℃.Theminimumcarboncontentinausteniteis0.77%at727℃.Basiciron-carbonalloyphaseingeneral,isahigh-temperatureausteniticorganization,stabletemperaturerangeof727~1394℃,sothehardnessofausteniteislow,highplasticity,usuallyinthesteelmaterialhotdeformationprocessing.σb=400MPa,170~220HBS,δ=40%~50%.Cementiteisformedofironandcarbonwithacomplexstructureofthemetalcompounds,withchemicalformulaFe3Cthatit'scarbonmassfractionWc=6.69%,meltingpointis1227℃.Cementiteishardandbrittle.Basiciron-carbonalloysteeliscementitephaseinthestrengtheningphase,cementiteaccordingtodifferentconditionstogenerateastrip,mesh,sheet,granularandothershape,theirsize,numberanddistributionofiron-carbonalloyshaveagreatimpact.Ironcarbonalloyphasediagram,mainlythreeprocess,BaoJing,eutectic,andGongXi.IncludingheattreatmentprocessingtemperaturegeneralwithGongXichangelineasthebenchmark.Highertemperaturecanmakesteeloverheating,leadtosteelpartscan'trepairandscrap.Temperatureistoolow,can'treachthetissuesthatneedandperformance,especiallyquenching.参考文献【1】赵程，杨建民.机械工程材料第2版.北京：机械工业出版社，2007【2】（美）PNRao.ManufacturingTeachnology-Foundry,ForrmingandWelfing.北京：机械工业出版社，2003【3】樊东黎徐跃明《热处理工程师手册\》北京机械工业出版社2011