Investigation of wear performance of R260 and R350HT rails after vibratory peening and ultrasonic nanocrystal surface modification

Abstract

In this study, the effects of ultrasonic nanocrystal surface modification (UNSM) and severe vibratory peening (SVP) of R260 and R350HT rail steels were investigated. The surface treatments resulted effective grain size reduction in the surface layers. While surface roughness decreased due to UNSM, SVP generally increased surface roughness. SVP demonstrated a significant effect on the microhardness. While the microhardness of the untreated sample was around 320 HV, the microhardness of R350HT peened for 4 h and 10 h increased to 390 and 470 HV, respectively. The UNSM treated specimens showed significant improvements, especially in surface roughness, which improved the wear performance. SVP treated specimens showed significant improvements in friction and wear performance due to the improvement on microhardness.