Initiation and evolution of wheel polygonal wear: Influence of wheel-rail hardness ratios.

Railway wheel polygonization is a type of uneven wear of material which worsens the running stability of trains. As a significant factor influencing the wear, wheel-rail hardness matching (i.e., the hardness ratio H W / H R) might affect the formation of a polygonal wheel. Thus, rolling-sliding wear tests were conducted using three wheel steels matching two rail steels to explore the influence of H W / H R (ranging from 0.649 to 1.263) on the initiation and evolution of wheel polygonal wear. The results show that when matching the softer rail, the wheel was less likely to become polygonal with an increase in H W / H R. When matching the harder rail, the wheel presented earlier polygon initiation under a moderate H W / H R of 0.792. The largest H W / H R of 1.263 presented the best anti-polygon condition for wheel material. The wear mechanism of polygonal wheel was dominated by abrasive, fatigue and oxidative wear at the crest and fatigue wear at the trough. • Evolution of wheel polygon wear is analyzed via rolling-sliding test with high-speed camera and vibration sensor. • Effect of wheel-rail hardness ratio on wheel polygon wear is explored. • Wheel polygon wear is easier to form with wheel hardness decreasing and rail hardness increasing. • Wear mechanism at crest is different with that at trough. [ABSTRACT FROM AUTHOR]