淬硬轴承钢GCr15磨削白层结构特性的实验研究  

Experimental Study on Characterization of White Layer Formed in Grinding Process of Harden Bearing Steel

作　　者：黄向明[1] 周志雄[1] 杨军[1] 夏启龙[1] 

机构地区：[1]湖南大学,长沙410082

出　　处：《中国机械工程》2009年第9期1119-1123,共5页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(50675063)

摘　　要：通过对淬硬轴承钢GCr15进行磨削加工,系统研究了磨削白层的结构特性。实验研究表明,磨削表面由白层和暗层组成,而磨削白层由晶粒很细小的隐晶马氏体、少量残余奥氏体和碳化物组成。白层硬度较高而暗层出现软化,高硬度白层是由于隐晶马氏体中高密度位错和超细晶粒相互作用而引起的强化。暗层硬度变化是由于磨削温度梯度导致不同的回火状态而引起的。磨削白层厚度随磨削深度增大而增大,其表面残余应力表现为拉应力,并随磨削深度的增大而增大。磨削白层的形成主要是磨削热和材料的塑性变形两种因素共同作用的结果。This paper investigated the microstructure of white layer formed in grinding process of GCr15 harden bearing steel. The experiment indicates ground surface consists of white layer and dark layer, and the whiter layer is made up of cryptocrystalline martensite, retained austenite and carbide. High hardness of white layer is caused by consolidation through extremely small grain size and high dislocation density. The changing hardness of the dark layer is ascribed different tempering situation induced by the gradient of the grinding tem- perature. The residual stress in white layer is tensile stress, and the value of the tensile stress increases with grinding depth. The depth of white layer increases with the grinding depth. The formation of ground white layer is due to grinding heat and plastic deformation.

关 键 词：磨削加工 白层 微观结构 微观硬度 残余拉应力 

分 类 号：TG580.1[金属学及工艺—金属切削加工及机床]