Micro/Nano Scale Wear Behavior of Pearlitic and Bainitic Rail Steels

Abstract

To develop rails with higher hardness and thus better durability and longer life, alternative microstructures have been suggested, since conventional pearlitic rail steels have reached their hardness limit. Such a newly developed material has a fine bainite microstructure (coded J6 bainitic steel) and showed higher initial hardness but poorer on-site wear performance, compared to conventional pearlitic steels. This was explained by the fact that pearlitic steels show significant work hardening under severe stress conditions, even though their initial hardness was lower. In this work, the wear behavior of pearlitic and J6 bainitic rail steels was investigated at the micro/nano scale, using the nanoscratch technique. It was found that pearlitic steel shows better wear performance at the micro scale as well, in agreement with large scale rail field tests.