Cause of Contact Fatigue Damage on U75 V 60 kg/m Rail

Aiming at the defect inspection alarming of U75 V60 kg/m rail in small radius curve section of heavy-haul railway,the tests of macroscopic appearance,non-metallic inclusion grade,macrostructure and microstructure examination of the alarmed rail were carried out and the results were analyzed. The analysis results show that the rail was in good condition after 400 million tons passage. The defect of the tested rail is contact fatigue crack,which is related to the rail operating conditions of and the railway line operation conditions. The defect is independent of the rail quality.