等温淬火时间对铁道机车用SAE8620轴承钢接触疲劳性能的影响  

Effect of Austempering Time on Contact Fatigue Performance of SAE8620 Bearing Steel for Railway Locomotive

作　　者：张文凯[1] 杨贞[1] 王克成 ZHANG Wenkai;YANG Zhen;WANG Kecheng(Locomotive Department,Baotou Railway Vocational and Technical College,Baotou 014060,China;School of Materials Science and Engineering,Jilin University,Changchun 130012,China)

机构地区：[1]包头铁道职业技术学院机车车辆系,包头014060 [2]吉林大学材料科学与工程学院,长春130012

出　　处：《机械工程材料》2022年第7期51-56,共6页Materials For Mechanical Engineering

基　　金：内蒙古自治区科技计划项目(19KJ98016)。

摘　　要：将表面渗碳处理的SAE8620轴承钢在855℃奥氏体化后,在225℃盐浴中进行等温淬火处理,再在225℃下进行回火处理,研究了等温淬火时间(7,21 h)对试验钢显微组织、物相组成、硬度和接触疲劳性能的影响。结果表明:等温淬火7 h时试验钢表层组织为贝氏体铁素体、残余奥氏体、马氏体和碳化物,等温淬火21 h后表层组织中的马氏体消失,贝氏体板条平均宽度增加,针状贝氏体铁素体含量增加,残余奥氏体含量减少;与等温淬火21 h相比等温淬火7 h试验钢的表层硬度更大,接触疲劳寿命也更长,这主要与其表层残余奥氏体含量更高、贝氏体板条平均宽度更小、表层硬度更大,可以更好地抵抗塑性变形有关。The surface carburized SAE8620 bearing steel was austenitized at 855 ℃, then subjected to austempering in a salt bath at 225 ℃, and then tempered at 225 ℃. The effects of austempering time(7, 21 h) on the microstructure, phase composition, hardness and contact fatigue properties of the test steel were investigated. The results show that the surface microstructure of the test steel was composed of bainitic ferrite, retained austenite, martensite and carbides when austempered for 7 h. When austempered for 21 h, the martensite in the surface structure disappeared, the average width of bainite laths increased, the content of acicular bainitic ferrite increased and that of the retained austenite decreased. The test steel austempered for 7 h had higher surface hardness and a longer contact fatigue life than the steel austempered for 21 h, which was mainly related to the better resistance to plastic deformation due to the more retained austenite, smaller average width of bainite laths in the surface and higher surface hardness.

关 键 词：等温淬火 轴承钢 显微组织 接触疲劳寿命 表面形貌 

分 类 号：TG142.1[一般工业技术—材料科学与工程]