关键词: 表层相变, 磨削强化, 温度场仿真

Abstract: The dissipated heat in grinding is utilized to induce martensitic phase transformation and strengthen the surface layer of 40Cr steel by raising surface temperature higher than austenic temperature and cooling quickly. The experiment of grinding 40Cr steel is taken in grinding machine. The metallurgical microstructure, depth and hardness of transect phase transformation layer are analyzed and surface roughness is measured. Temperature field and temperature history are simulated based on finite element method. The simulated hardness penetration depth is deduced from every place temperature history of work piece and martensitic phase transformation conditions. The experiment result shows that martensitic phase transformation takes place on the 40Cr steel surface layer in grinding, the hardness of surface layer is improved highly and surface roughness accords with the roughness of traditional grinding. So, it is possible for grind-hardening to take place of induction hardening. The temperature field and history can be simulated based on finite element method to predict the hardness penetration depth and optimize the grinding parameters. Thus the experiment cost and time can be reduced.

Key words: Temperature field simulation, Grind-hardening, Surface phase transformation