Effects of abrasive material and hardness of grinding wheel on rail grinding behaviors

摘要

Abrasive material and hardness of grinding wheel are two important factors affecting the grinding efficiency and quality. In this study, two kinds of abrasive grains (i.e., zirconium corundum (ZA) and brown fused alumina (BA)) were used to produce eight grinding wheels, among which five with different contents of abrasive grains and four with different hardness levels. Rail grinding experiments were conducted to investigate their grinding efficiency (grinding amount of rail), grinding quality (including surface roughness, surface burn, white etching layer (WEL), and residual stress), and wear types of grinding wheels. The results show that ZA grinding wheel produced larger grinding amount, higher surface roughness, but lower level of surface burn, thinner WEL, and smaller parallel residual stress than BA grinding wheel. With the increase in grinding wheel hardness, the surface roughness and residual stress of ground rail showed decrease trends, but the thickness of WEL increased. The wear type of ZA grains was macro-fracture and the wear type of BA grains was attrition wear. With the increase in grinding wheel hardness, the wear type was changed from grain pullout wear to macro-fracture. Based on the analysis of results, the appropriate grinding wheel was recommended that can improve the grinding process and reduce the grinding cost.