提高轴承钢性能的热处理工艺研究

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1、西南交通大学硕士学位论文提高轴承钢性能的热处理工艺研究姓名：王林梅申请学位级别：硕士专业：材料科学与工程指导教师：杨川20081101西南交通大学硕士研究生学位论文第1I页到的组织组成为针状马氏体+下贝氏体+残余奥氏体+残余碳化物。等温初期，贝氏体转变较快，下贝氏体随等温时间延长而长大，等温到一定时间后下贝氏体转变速率下降，贝氏体不再继续长大。贝氏体转变量在45．1％左右时，轴承试样的综合性能最佳。耐磨性能比马氏体淬回火试样提高了47．5％。GCrl5经马氏体淬回火处理，试样断裂机制为微孔聚集型断裂，而经贝氏体等温淬火处理后，断裂机制转变为解理断裂。贝氏体转变后试样表面的残余压应力高于

2、马氏体淬回火组织。关键词：轴承钢，细化碳化物，残余奥氏体，下贝氏体，MfB复合组织，性能西南交通大学硕士研究生学位论文第lII页AbstractRecently,withthefastdevelopmentofwindelectricpowerprojectsand11j曲speedrailway,RollingBearingiswidelyusedinengineering，andtheservicelifeisrequiredtobecomehigherandhigher．Thispaperbasedonimprovingthepropertiesofbearingsteelsth

3、roughheattreatment，determinedthemicrostructureandmechanicalpropertiesofseveraldomesticandextemalbearingsteelsamples．andtheretentionofausteniteofdifferentsamplesweremeasuredbymeansofXRD．SEMwasusedtOanalysisthedifferenceinstructureofseveralbearingsteelsamples．Onthisbasis．thecarbideWasrefinedbyvari

4、ouspretreatmentprocess，andthemicrostructureandmechanicalpropertiesofsamplesweremeasuredafterdifferentheattreatment．Theresidualaustenitecontentwascontrolled，indifferentrangesbyultimatetreatmenttechnology，themicrostructuresandthemechanicalpropertiesareexamined．andtheinfluenceofresidualaustenitecon

5、tentonpropertiesofbearingsteelshavebeenanalyzed．Themicrostructuresandmechanicalpropertiesofbearingsteelwereinvestigatedafteraustemperingfordifferentisothermalholdingtime．Bainitetransformationrateanditseffectonbearingsteelpropertieswereresearched．SEMwasusedtoanalysisfracturemechanismandXRDwasused

6、tomeasuretheresidualstressofsamplesaftermartensiticquenchingandbainitehardening．Basedontheresearchwork，someconclusionsaredrawnasfollows：Themartensitecontentofshaftsleeveandaxostyleofexternalbearingstee】arecontroledrespectivelyindifferentranges．Comparingwithdomesticbearing，theexternalbearingsteel

7、shavewelldistributedfinelycarbides，andIowerresidualaustenitecontent．Indeed．theresidualaustenitewaseliminatedcompletelyinsomeexternalbearingsteels．Experimentalresultsindicatethattheexternalbearingsteelexhibitsabeaerwearresist