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1、第40卷第8期Vol暢40No暢82015年8月HEATTREATMENTOFMETALSAugust2015馬氏體鋼雙相區(qū)奧氏體組織特征及形成機(jī)理111112陳連生,張健楊,田亞強(qiáng),宋進(jìn)英,魏英立,徐勇(1.華北理工大學(xué)河北省現(xiàn)代冶金技術(shù)重點(diǎn)試驗(yàn)室,河北唐山063009;2.中國(guó)科學(xué)院金屬研究所,遼寧沈陽110016)摘要:采用雙相區(qū)再加熱-淬火(IQ)工藝,研究了馬氏體鋼在雙相區(qū)再加熱過程中奧氏體的組織特征及形成機(jī)理。結(jié)果表明,經(jīng)890℃奧氏體化900s后淬火處理獲得板條馬氏體組織的試驗(yàn)鋼,經(jīng)隨后的雙相區(qū)750℃再加熱-
2、淬火處理,在馬氏體組織的基礎(chǔ)上獲得了由亞溫鐵素體和塊狀或針狀馬氏體組成的雙相組織。馬氏體鋼在雙相區(qū)再加熱過程中,針狀?yuàn)W氏體的形成過程可以分為3個(gè)階段:以板條馬氏體間碳化物(Fe3C)為奧氏體形核點(diǎn)及C元素在奧氏體內(nèi)的擴(kuò)散控制奧氏體在板條界間生長(zhǎng);板條馬氏體內(nèi)C向奧氏體內(nèi)擴(kuò)散控制其沿板條方向長(zhǎng)大;Mn向奧氏體擴(kuò)散并控制鐵素體-奧氏體兩相達(dá)到最終的平衡狀態(tài)。鋼在750℃再加熱過程中,C、Mn元素由鐵素體向奧氏體相中擴(kuò)散,其擴(kuò)散過程控制著奧氏體的形核與長(zhǎng)大,擴(kuò)散的結(jié)果是C、Mn元素在奧氏體內(nèi)富集,實(shí)現(xiàn)C、Mn元素在兩相之間的配分。
3、關(guān)鍵詞:馬氏體鋼;雙相區(qū)再加熱;奧氏體;組織特征;元素配分中圖分類號(hào):TG142.4文獻(xiàn)標(biāo)志碼:A文章編號(hào):0254-6051(2015)08-0068-05Austenitemorphologyfeatureandnucleationmechanismduringintercriticalreheatingofmartensitesteel111112ChenLiansheng,ZhangJianyang,TianYaqiang,SongJinying,WeiYingli,XuYong(1.HebeiKeyLaborato
4、ryofModernMetallurgyTechnology,NorthChinaUniversityofScienceandTechnology,TangshanHebei063009,China;2.InstituteofMetalResearch,ChineseAcademyofSciences,ShenyangLiaoning110016,China)Abstract:Theaustenitemorphologyfeatureandnucleationmechanismduringintercriticalrehea
5、tingofthemartensitesteelwereinvestigatedbymeansofintercriticalreheating-quenching(IQ)heattreatment.Theresultsshowthatlathmartensitecanbeobtainedafteraustenitizingat890℃for900sandquenching.Thedualphasescontainedlathferritematrixandneedle-likeorblockmartensiteinthema
6、rtensitesteelcanbegainedafterthesubsequentheattreatmentofintercriticalreheatingat750℃-quenching(IQ).Thetransformationofneedle-likeausteniteduringintercriticalannealingisdividedintothreestageswhenthemartensitesteelisreheatedinthetemperaturerangeofthedual-phaseregion
7、.Thefirststageconsistsofnucleationofneedle-likeausteniteatthecarbides(Fe3C)betweenmartensitelathsandgrowthofaustenitebetweenmartensitelathscontrolledprimarilybycarbondiffusionintheaustenite.Subsequentgrowthoftheaustenitebetweenmartensitelathstoachievepartialequilib
8、riumiscontrolledbycarbondiffusionintheaustenite.Atlast,thefinalequilibrationoftheferriteandausteniteisachievedbyMndiffusionthroughtheaustenite.Du