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Fe20.28%C23.0%MoEffectofHighMagneticFieldonFerriteTransformationinFe20.28%C23.0%MoAlloy,,(,430081)ZHOUZhen2ni,ZHANGJing2jing,WUKai2ming(InstituteofAdvancedSteelMaterialsandWeldingTechnology,HubeiProvinceKeyLaboratoryforSystemsScienceonMetallurgicalProcessing,WuhanUniversityofScienceandTechnology,Wuhan430081,China):12TFe20.28%(,)C23.0%Mo,,TTT(temperature2time2transformation)610,640,:;;;;:TG111;TG142:A:100124381(2009)0820010205Abstract:ThetransformationofdegenerateferriteinanFe20.28%C23.0%Moalloywasinvestigatedbyisothermalholdingundera12Tmagneticfield.Thedegenerateferritewasobservedaroundandbe2lowthebaytemperaturewithandwithoutthemagneticfield.Theresultsshowthatthedegenerateferritetransformationisacceleratedbyapplyinga12Tmagneticfield.ThebaytemperatureofTTT2curvesisraisedinmagneticfield,i.e.Thebaytemperatureisabout610withoutamagneticfieldwhereasitbecomesapproximately640witha12Tmagneticfield;becausethefreeenergyofdegen2erateferriteisloweredbyahighmagneticfield.Keywords:lowalloysteel;highmagneticfield;ferrite;phasetransformation;molybdenum,,,,MoMo,Mo,,,Mo,Fe2C2Mo[1-3]Fe2C2Mo:(1)Mo[4];(2)[5](3)TTT(temperature2time2transformation)[5];(4)[6];(5)[6];(6)[7],,,,Fe20.28%C23.0%Mo,101/20098,125048h,14mm4mm18mm,191030min,,(530640)(1010000s),-33%(),(PointCounting)[8],(50)(S),(500)(S),S=SS1(/%)Table1Chemicalcompositionofsteelsample(massfraction/%)CSiMnPSMo0.280.010.010.010.013.01Fig.1Schematicdiagramofahighmagneticfieldheattreatmentapparatus22.1TTT20,60,600,3600,10000s20s,,,570590,590TTT,Fe2C2Mo:TTT,,,3600s,590(15.9%);5703600s16.1%530,3600sFe2C2Mo[6],12T2(%)Table2Volumefractionofferritetransformedwithoutahighmagneticfield(%)Temperature/20s3600s5302.71005501.429.65701.916.15902.915.96104.129.7,TTT22,,Tb610,,Tb640,Tb302,2TTT(a);(b)Fig.2MeasuredTTTcurvesofferritetransformation(a)witha12Tmagneticfield;(b)withoutamagneticfield11Fe20.28%C23.0%Mo2.236103,20s,(3a)60s(3b)600s3600s,,(3c,Popcorn2like),,,3610(a)20s;(b)60s;(c)600sFig.3Opticalmicrographsofspecimensisothermallyheldat610fordifferenttimewithoutahighmagneticfield(a)20s;(b)60s;(c)600s412T61060s,(4a)600s,(4b),(4c)412T610(a)60s;(b)600s;(c)3600sFig.4Opticalmicrographsofspecimensisothermallyheldat610for60s(a),600s(b),and3600s(c)witha12Tmagneticfield2.355305a,20s,20s,,,(5b)612T5306,530,,(6a)10s21/2009820s,3600s100%(6b)33.1,,,,[9,10][11,12][13,14],2,Ohtsuka[14]10TFe23.6Ni21.5Cr20.5C,10T0.080.973.2TTT,[14]Ohtsuka[14]10TFe23.6Ni21.5Cr20.5C,40,,,TTT()C[15],[6]TTT,2,[5,6,8,15-18]4(1),;,(2)TTT31Fe20.28%C23.0%Mo610,640[1]HUMPHREYSES,FLETCHERHA,HUTCHINSJD,etal.Molybdenumaccumulationatferrite:austeniteinterfacesduringisothermaltransformationofanFe20.24PctC20.93PctMoalloy[J].MetallMaterTransA,2004,35:1223-1235.[2]HACKENBERGRE,SHIFLETGJ.AmicroanalysisstudyofthebanitereactionatthebayinFe2C2Mo[J].ActaMaterialia,2003,51:2131-2147.[3]ENOMOTOM,WUKM,KAGAYAMAM.Influenceofmag2neticfieldonferritetransformationinFe2C2Moalloy[J].CAMP2ISIJ,2004,17:1223-1226.[4]RIDLEYN.Thepearlitetransformation[M].Warrendale:TMS2AIME,1983.201-236.[5]TSUBAKINOH,AARONSONHI.Ferriteandcarbidemor2phologiesinandbelowthebayregionofanFe20.19CPct22130PctMoalloy[J].MetallTransA,1987,18:2047-2060.[6]REYNOLDSWT,JR,LIFZ,etal.Theincompletetransfor2mationphenemenoninFe2C2Moalloys[J].MetallTransA,1990,21:1433-1463.[7]SHTANSKYDV,INDENG.PhasetransformationinFe2Mo2CandFe2W2Csteels$.thestructualevolutionduringtemperingat700[J].ActaMater,1997,45:2862-2878.[8]WUKM,KAGAYAMAM,ENOMOTOM.KineticsofferritetransformationinanFe20128mass%2310mass%Moalloy[J].MaterScieEng,2003,A343:143-150.[9]ENOMOTOM,GUOH,TAZUKEY,etal.Influenceofmag2neticfieldonthekineticsofproeutectoidferritetransformationinironalloys[J].MetallMaterTrans,2001,32A:445-453.[10]LUDTKAGM,JARAMILLORA,KISNERRA,etal.Insi2tuevidenceofenhancedtransformationkineticsinamediumcar2bonsteelduetoahighmagneticfield[J].ScripMater,2004,51:171-174.[11]KAKESHITAT,KUROIWAK,SHIMIZUK,etal.AnewmodelexplainableforboththeathermalandisothermalnaturesofmartensitictransformationinFe2Ni2Mnalloys[J].MaterTrans,1993,34:423-428.[12]OHTSUKAH,HAOXJ,WADAH.EffectsofmagneticfieldandprioraustenitegrainsizeonthestructureformedbyreversetransformationfromlathmartensitetoausteniteinanFe20.4Calloy[J].MaterTrans,2003,44:2529-2531.[13]OHTSUKAH.Effectofstrongmagneticfieldsonbainitictrans2formation[J].CurrOpinSolidStateMaterSci,2004,8:279-284.[14]OHTSUKAH.Effectsofahighmagneticfieldonbainitictrans2formationinFe2basedalloys[J].MaterSciEng,2006,A438-440:136-139.[15]SHIFLETGJ,AARONSONHI.Growthandoveralltransfor2mationkineticsabovebaytemperatureinFe2C2Moalloys[J].MetallTrans,1990,21A:1413-1432.[16]FLETCHERHA,GARRATT2REEDAJ,AARONSONHI,etal.Astemmethodforinvestigatingalloyingelementaccumu2lationataustenite:ferriteboundariesinanFe2C2Moalloy[J].ScriptaMater,2001,45:561-567.[17]WUKM,ENOMOTOM.Three2dimensionalmorphologyofdegenerateferriteinanFe2C2Moalloy[J].ScripMater,2002,46:569-574.:(NCET20520680);(2006ABB037):2009201222;:2009206213:(1981),,,,E2mail:147829sea@163.com:(1966),,,,,:9478#(430081),E2mail:wukaiming@wust.edu.cn;wukaim2ing200