关键词: 钢轨, 裂纹扩展, 磨损, 疲劳裂纹, 塑性变形

Abstract: The rolling tests for four types of railway rails: quenched PD3, hot-rolled PD3, quenched U71Mn and hot-rolled U71Mn are performed using a JD-1 wheel/rail simulation facility with Hertz simulation method, which can ensure the reciprocal contact condition between simulation rail and wheel under experimental conditions approximate to practical contact conditions. Mechanical photoelectric analytical balance is adopted to check wear volume of rail specimens. Optical microscopy (OM) and scanning electronic microscopy (SEM) are used to perform micro-analysis on rail rolling specimens, providing guidance for rail material choosing of high speed railway. The results indicate that rail material with a higher hardness appears less wear volume and thinner plastic deformation layer after rolling test, however, the crack propagation of which is deeper and fatigue damage is more severe, showing better wear resistance. Meanwhile, rail material with a lower hardness appears more wear volume and thicker plastic deformation layer, but its fatigue damage is slight because of the removal of a part of just-initiated micro cracks. The analysis shows that U71Mn rail with better fatigue resistance is more suitable for the high-speed railway, considering fatigue is the main cause for the damage of high-speed rail.

Key words: Crack growth, Fatigue crack, Plastic deformation, Rail, Wear