Experimental study on grind-hardening of GCr15 steel with CBN grinding wheel

ZHANG Yu, LIANG Guo-xing, ZHANG Hao, HAO Jian-yu, CHENG Qiang
(College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan 030024, China)

Abstract: In order to provide more theoretical basis for the grind-hardening process, CBN grinding wheel was used for the grindhardening test of GCr15 steel, the changes of the grinding organization during the grind hardening process and the influence of the grinding parameters on the hardness and distribution of the hardened layer were analyzed and studied.The darkfield microscope was used to observe the microstructure changes of GCr15 steel before and after grinding, and the reasons for the microstructure changes were analyzed. The microVickers hardness tester was used to analyze the hardness uniformity of the hardened layer and the causes of the hardness nonuniformity. The influence of the grinding parameters on the hardness of the hardened layer was studied by the grindhardening test group, and the causes of such effects were analyzed from the perspective of grinding heat. The results indicate that the depth of the hardened layer is 0.12 mm, the transformation of the microstructure of the workpiece is the main factor affecting the hardness uniformity of the hardened layer during the grinding process. Properly increasing the grinding depth and workpiece feed rate can achieve higher hardness of the hardened layer, and increasing the cooling rate of the workpiece can also increase the hardness of the hardened layer.
Key words: grind-hardening; GCr15; hardness distribution; consistency; grinding heat