盾构机主轴承套圈表面淬火工艺  

Surface Quenching Process for Rings of Main Bearings for Shield Tunneling Machines

作　　者：封少波[1] 吴长江 袁麟 胡小强[1] 李殿中[1] FENG Shaobo;WU Changjiang;YUAN Lin;HU Xiaoqiang;LI Dianzhong(Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所、沈阳材料科学国家研究中心,沈阳110016

出　　处：《轴承》2024年第11期121-127,共7页Bearing

摘　　要：盾构机主轴承服役时需承受交变重载等恶劣工况,其套圈滚道表淬层要求具有足够的深度,较高的强度和硬度以及良好的抗疲劳和耐磨损等性能;但淬硬层过深易导致显微组织粗大,淬火残余应力高,甚至出现淬火裂纹等问题。为实现套圈滚道表淬层深度与性能调控,分析了冷却方式、加热温度和时间、低温回火温度对42CrMo4M钢淬硬层的深度、硬度、显微组织和残余应力的影响,结果表明:水淬的淬硬层硬度和深度高于油冷和喷水;加热温度为870~920℃,加热时间为20~60 s,水淬时的淬硬层深度均达到14 mm以上,表层硬度不小于54 HRC,其中加热温度为900℃,加热时间为40~60 s时的淬硬层深度最大,硬度最均匀;低温回火温度在150~300℃时,随着回火温度升高,淬硬层硬度下降,残余应力减小,基体逐渐析出碳化物。最佳表面淬火工艺为加热温度900℃、加热时间40 s、水淬冷却,低温回火温度不大于210℃,采用该工艺完成了Φ7.6 m主轴承套圈工程样件滚道的表面淬火,套圈滚道表面淬硬层深度为10.5 mm,表面硬度不小于55 HRC,淬硬层组织主要为板条马氏体。The main bearings for shield tunneling machines experience harsh working conditions such as alternating heavy loads during service,therefore the quenched layer on ring raceway surface requires sufficient depth,high strength and hardness,as well as good fatigue and wear resistance.However,too deep quenched layer can easily lead to coarse microstructure and high quenching residual stress,even resulting in quenching cracking.In order to achieve the control of depth and properties of quenched layer on ring raceway surface,the effects of cooling method,heating temperature and time,and low tempering temperature on depth,hardness,microstructure and residual stress of quenched layer of 42CrMo4M steel are analyzed.The results indicate that the layer quenched by water cooling method has a higher hardness and deeper depth than those of oil cooling and water spray cooling methods;by adopting the process of heating at 870~920℃for 20~60 s,and quenched by water cooling,the depth of quenched layer is more than 14 mm,and the surface hardness is not less than 54 HRC,the deepest quenched layer and the most uniform surface hardness distribution are obtained when quenched at 900℃for 40~60 s;the hardness and residual stress of quenched layer reduce as low tempering temperature increasing in the range from 150℃to 300℃,while carbides in matrix gradually precipitate.Therefore,the suitable surface quenching parameters are determined as quenching at 900℃for 40 s,subsequently water cooling,and tempering below 210℃.Finally,the surface quenching of raceway ofΦ7.6 m ring sample for main bearing is completed by this process.The depth of quenched layer on ring raceway surface is 10.5 mm,the surface hardness is not less than 55 HRC,and the microstructure of quenched layer is mainly lath martensite.

关 键 词：滚动轴承 盾构机轴承 热处理 感应淬火 低温回火 硬度 残余应力 

分 类 号：TH133.33[机械工程—机械制造及自动化] TG156.33[金属学及工艺—热处理]