22CrSH齿套钢热处理工艺及组织性能

（工程硕士）22CrSH齿套钢热处理工艺及组织性能HEATTREATMENT,MICROSTRUCTUREANDPROPERTIESOF22CRSHGEARBOXSTEEL刘宏光哈尔滨工业大学2007年4月图书分类号：TG142.25U.D.C.:669工程硕士学位论文22CrSH齿套钢热处理工艺及组织性能硕士研究生：刘宏光导师：甄良教授副导师：徐香秋高级工程师申请学位级别：工程硕士学科、专业：材料学所在单位：长春一汽集团答辩日期：2007年4月授予学位单位：哈尔滨工业大学ClassifiedIndex：TG142.25U.D.C.:669ADissertationfortheDegreeofMasterofEngineeringHEATTREATMENT,MICROSTRUCTUREANDPROPERTIESOF22CRSHGEARBOXSTEELCandidate:LiuHongguangSupervisor:Prof.ZhenLiangAssociateSupervisor:SeniorEngineer.XuXiangqiuAcademicDegreeAppliedfor:MasterofEngineeringSpeciality:MaterialsScienceAffiliation:ChangchunFirstAutomobileGroupDateofOralExamination:April,2007University:HarbinInstituteofTechnology哈尔滨工业大学工程硕士学位论文-I-摘要本文针对红旗轿车016传动器同步器齿套生产中存在的问题，研究了新型齿套材料22CrSH钢奥氏体化温度、变形、冷却速度对相转变、相组织的影响，以及22CrSH钢的切削性能和热处理工艺，获得了以下研究结果：在奥氏体状态下，22CrSH钢的变形处理，促进了连续冷却相变，相变区左移；随着冷却速度的降低，奥氏体变形程度的增加，连续冷却相变组织中先共析铁素体和珠光体体积百分数增多，金相组织细小，完全获得先共析铁素体+珠光体组织的临界冷却速度增大。22CrSH钢中的MnS能均匀奥氏体晶粒，对奥氏体向先共析铁素体、贝氏体、WF及铁素体的相变有一定的促进作用。22CrSH钢正火后的显微组织为块状铁素体+珠光体组织，夹杂物以硫化物为主，非金属夹杂物、晶粒度及低倍组织满足加工和使用要求；机械性能良好，断屑性能好，切削性能略好于28MnCr5。22CrSH齿套、倒档惰轮渗碳和碳氮共渗后零件表面层硬度呈梯度分布，从表层至心部硬度变化平缓，心部硬度适中，与渗碳层相比，碳氮共渗层显微硬度略有升高，表面硬度稍大。经渗碳淬火后齿套、倒档惰轮表层组织为为针状马氏体加残余奥氏体；心部为板条马氏体；经碳氮共渗淬火后表层组织为马氏体+弥散分布的碳氮化合物+残余奥氏体；渗碳和碳氮共渗热处理后齿套外齿跨棒距和内齿跨棒距尺寸均略有增大。工件热处理变形是由热应力与组织应力综合作用的结果。渗碳和碳氮共渗热处理的齿套、倒档惰轮由于表层和心部化学成分、组织结构、冷却速度和淬火温度的不同，造成零件尺寸公差增大。关键词22CrSH钢；热处理工艺；微观组织；加工性能哈尔滨工业大学工程硕士学位论文-II-AbstractTheeffectofaustenitizationtemperature,deformationandcoolingrateofnewgearsteel22CrSHforgearcaseonphasetransformationandphasemicrostructure,cuttingpropertiesandheattreatmentprocesswereinvestigatedinthepaperaccordingtotheproblemofgearcaseoftransmissionpartsynchromesshpartfor016RedFlagcar.Austenitedeformationof22CrSHsteelmakesthephasetransformationathightemperatureimproved,coolingratesthatallkindsofphasetransformatiomsoccurredincreaseandthebeginningtimeofphasetransformationshiftsleft.Thecriticalcoolingrateoffullypre-eutectoidferriteandpearlitegainsandimprovesthephasetransformationofferriteandpearlitewithcoolingratedecreaseandtheextentofaustenitedeformationincrease,thevolumepercentofpre-eutectoidferriteandpearlitegains,finemicrostructures.MnSinclusionin22CrSHsteelcanmakeaustenitecrystallinegrainuniformandpromoteaustenitetransformationtopre-eutectoidferrite,bainite,WFandpearlitetosomeextent.Microstructureof22CrSHsteelafternormalizingtreatmentisferriteandpearliteandMnSisthemaininclusion.Sulphidenon-metallicinclusion,crystallinegraingradeandlowmagnitudemicrostructuresatisfytherequirementofprocessandapplication.Mechanicalandbrokenmetalfillingspropertiesof22CrSHsteelaregood.Cuttingpropertiesof22CrSHsteelarebetteralittlethanthatof28MnCr5steel.Surfacelayerhardnessofgearcaseandreversegearof22CrSHsteelaftercarburizationandcarbonitridingandquenchchangedgraduallyfromexternalsurfacetotheinternal.Thecenterareahardnessisadaptive.Comparingwithcarburizationlayerthehardnessofcarbonitridinglayershiftsslightlyandsurfacehardnessincreasesalittle.Microstructureofcarburizationsurfacelayerisneedle-likemartensiteandresidualaustenite,thecenterareaisslipaustenite.Microstructureofcarbonitridingsurfacelayerismartensite+distributedcarbonnitridecompound+residualaustenite.Overstickdistancetoleranceofexternalteethandinternalteethofgearcaseaftercarburizationandcarbonitridingboth哈尔滨工业大学工程硕士学位论文-III-increase.Heattreatmentdeformationofthepartsisowedtothermaltressandphasestressaffectseachother.Thepartssizetolerancerisesbecausesurfacelayerandthecenterareahavedifferentmicrostructures,composites,coollingratesandquenchtemperaturesaftergearcaseandreversegearcarburizationandcarbonitriding.Heattreatmentprocessisneededtoimprovetoreducepartsheattreatmentdeformation.Keywords22CrSHsteel,heattreatmentprocess,microstructrues,machiningproperties哈尔滨工业大学工程硕士学位论文--IV目录摘要.............................................................................................................................IAbstract......................................................................................................................II第1章绪论..............................................................................................................11.1引言.................................................................................................................11.2渗碳钢的研究状况.........................................................................................31.2.1渗碳钢的合金化原理............................................................................31.2.2渗碳钢的渗前热处理工艺....................................................................41.2.3渗碳钢的渗碳和碳氮共渗工艺............................................................51.3易切削钢的研究.............................................................................................61.4常用齿套钢的生产应用现状.........................................................................81.4.128MnCr5齿套钢....................................................................................81.4.228MnCr5齿套钢的应用及问题............................................................81.4.322CrSH齿套钢.................................................