退火轴承钢磨削白层的形成机理研究  

Research on Formation Mechanism of White Layer in Grinding of Annealed Bearing Steel

作　　者：黄向明[1] 周志雄[1] 杨军[1] 汤爱民[1] 

机构地区：[1]湖南大学,长沙410082

出　　处：《中国机械工程》2010年第24期3018-3023,共6页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(50675063)

摘　　要：采用热电偶技术和三向压电晶体测力仪,分别在线测量了退火轴承钢GCr15在不同磨削条件下接触区的温度和磨削力,利用扫描电镜(SEM)和X射线衍射仪(XRD)对磨削表面白层组织形态、残余奥氏体、组织亚晶粒以及微观应变进行了分析,并通过有限元软件分析砂轮磨粒对工件表面的接触应力和应变,探讨了退火钢磨削白层的形成机理。结果表明:退火钢白层组织中存在超细粒隐晶马氏体和少量残余奥氏体等组织。磨削白层是相变的产物,但可在低于材料名义相变温度Ac1的条件下产生。白层的形成条件是磨削过程快速升温和快速冷却以及磨削力引起材料的强烈塑性变形和高接触应力,塑性变形和接触应力能降低材料相变温度和细化晶粒。During the grinding process of GCr15 annealed bearing steel,the grinding temperature and the grinding force were measured on line by using the thermocouple technique and 3-axis piezoelectric dynamometer respectively.The microstructure,residual austenite content,sub-grain size and micro-strain were detected with scanning electron microscope and X-ray diffraction.The contact stress and plastic strain of grinding surface were simulated by using the finite element method.White layer formation mechanism of annealed steel was discussed.The results indicate white layer consists of cryptocrystalline martensite and retained austenite.The white layer is a product of phase transformation,but may generate at temperatures below the nominal austenitization temperature of the steel.Rapid heating and rapid cooling,plastic deformation and high contact stress result in white layers in grinding process.Plastic deformation and high contact stress can reduce phase temperature and refine crystal grain.

关 键 词：磨削白层 磨削温度 塑性变形 接触应力 相变 

分 类 号：TG580.1[金属学及工艺—金属切削加工及机床]