低碳粒状贝氏体钢强韧化机理的探讨

:1004-2261(2000)01-011-05X1,1,2(1.,300191;2.,110006):14SiMn3Mo.:,,.300,400-500.,.:;;:TG142.1:AStudyonthemechanismofstrengtheningandtougheningoflow2car2bonbainiticSteelZHAOJie1,WANGZhi2qi1,LIJian2ping2(1.Dept.ofMaterialsSci.&Eng.,TianjinInstituteofTechnology,Tianjin300191,China;2.RollingTechniqueandTandemAutomationNationalKeyLaboratory,NortheasternUniversi2ty,Shenyang110006,China)Abstract:Themicrostructure,strengthandtoughnessof14SiMn3Molow-carbonbainiticsteel2havebeenstudied.Theresultsshowthatthestructureofthesteelafteraircoolingisgranularbai2nite.Itexhibitspoortoughnessandlowratioofyieldtotensilestrength.Theoptimumcombina2tionofstrengthandtoughnesscanbeobtainedforthesteeltemperedat300.Temper2embrit2tlementevidentlyoccursintherangeof400500.Accordingtothechangesofmicrostructureandstabilityofretainedaustenite,themechanismofstrengthening2tougheningandtemper2embrit2tlementoflow2carbonbainiticsteelisdiscussed.Keywords:granularbainite;strengtheningandtoughening;temperingHarbraken,,110.,,..,,,5,9,(M-A).8,10,,,,..114SiMn3Mo.:930,200650,1.5h.MM6H80016120003JOURNALOFTIANJININSTITUTEOFTECHNOLOGYVol.16No.1Mar.2000X:1999-12-10:(1958-),,©1995-2005TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved..do=10mm,lo=5do.V,CIEM-30-CPC,.MSF-2MX.(AR)238.73kA/m.9.030.0mm,AR=0.2%1.2%.22.19301.:1Fig.1Therelationshipbetweenmechanicalpropertiesandtemperingtemperature1),,(0.2/b=0.69).2)(b)450;(0.2),300,(0.2/b=0.84).3)(akv),300akv,450,akv..2.214SiMn3MoFig.2Impactexperimentalresultsof14SiMn3Mosteel(obtainedbyelectronicoscillography)-,300,,.,450,,,,.:,400500.2.2ARAR1.:,AR,=0.2%=1.2%,17%24%AR.300450,AR,.AR,,2.8%5.6%AR;AR,0.2%,AR25%.550,AR,AR.,550,.2116©1995-2005TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.1ARTable1StabilityofretainedausteniteandretainedstressunderdifferentheattreatmentconditionsHeattreatmentprocess=0%=0.2%=1.2%AR%AR%Relativetransfor-mation%%AR%Relativetransfor-mation%%Retainedstress(MPa)(MPa)930Normalized93010.48.6177.924208930Normalized+300tempered930+3007.16.92.86.75.653930Normalized+450tempered930+4506.75.0252.56216930Normalized+550tempered930+5502.11.3381.05202.31),3..,(M)(A)M/A.,M/A36%.ARM/A(BF).3800Fig.3Normalizedmicrostructure800M/AM(4).BF(5).2)6300.,M/A.,AR,BF(7)M/A(8).450,,M/A(9).,M/A,,Fe3C(10).,BFAR,Fe3C.4M/A(20000)Fig.4TwinnedmartensiteinM/Aisland(brightfield20000)5BF(20000)Fig.5DislocationsinBFlaths(brightfield20000)311:©1995-2005TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.6300800Fig.6Microstructureaftertemperingat3008007300BFAR(20000)Fig.7ARfilmsbetweenBFlathsaftertemperingat300(darkfield20000)8300M/AAR(20000)Fig.8ARfilmsaroundM/Aislandaftertemperingat300(darkfield20000)9450800Fig.9Microstructureaftertemperingat450800(a)(brightfield)20000(b)(darkfield)20000(c)(SADpattern)(d)(indexing)10450M/AFig.10Carbideprecipitateaftertemperingat4504116©1995-2005TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.550,.33.1,,,.,M/AMAR;AR.300,BF,BF.M/A.,,M/A.30%AR,.70%AR,BFM/A.,AR,AR,M.,AR,AR,AR,ARMd,M,AR.,AR,,,.AR,AR.,,,AR,,M/AMM,,,9,10.300,ARAR.3.2:400500,.1,450,AR300,.BFAR,,,,.M/AFe3C,.AR,,M,MM,,.AR,,AR;,ARMd.41)Si,..2)(300).M/AMM,AR.3)400500,M/ABFARFe3C,AR.:1,,.[J].,1990,():4049.2,.[J].,1996,32(9):897903.3,.[J].,1999,23(1):2729.4,,.[J].,1988,(11):113.5.[J].,1991,(3):411.6.[J].,1998,(11):27.7,.12CrMoV[J].,1996,17():8489.8.AR[J].,1994,(5):1216.9,.[J].,1990,():133139.10.[J].,1989,(11):1621.511:©1995-2005TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.