Influences of Grinding Mark Roughness and Cross Marks on Rolling Contact Fatigue Damage of Rail

Grinding marks with different roughness levels (1, 4, 7 μm) and cross grinding marks were produced on the rail samples using abrasive papers. Then, rolling tests were conducted using those ground rail samples on the MMS-2A wheel/rail friction and wear machine. After that, the rolling contact fatigue of ground rail was analyzed. The results indicated that the roughness and damage of worn surfaces of ground rails were severer than those of unground rails. With the increase in the grinding roughness, the roughness and damage of worn rails showed a decrease trend. When the grinding roughness was 7 μm, branch cracks were generated, the depth of cracks was small. With the decrease in grinding roughness, branch cracks connected with each other, then net-like cracks were generated, the depth of cracks was increased. When the rails were ground with cross grinding marks, the roughness and rolling contact fatigue damage of worn rails were alleviated. The rolling damage of the ground rail with the −45°/70° and 45°/70° cross marks was milder than that of −20°/90° cross marks.