ROLLING SLIDING WEAR BEHAVIOR OF 3 BAINITIC STEELS

Railroad rails and wheels are produced from fully pearlitic eutectoid steel. Until very recently it has been a commonly held view that bainitic steels, although offering advantages in terms of toughness and weldability, could not compete with the wear resistance of pearlitic steels. Rolling-sliding wear tests have been carried out on three bainitic steels with 0.04, 0.10 and 0.52 wt.% C. The contact conditions employed simulate the most severe wear situation encountered by wheels and rails in curved track. Wear resistance was not dominated by initial hardness. The lowest carbon steel, with a granular bainite structure and a Rockwell hardness of 29 HRC, provided the best performance. Its wear resistance was comparable with that of a conventional pearlitic steel with a hardness of 33 HRC. The results confirm the potential of bainitic steels for wear resistance, particularly at high contact pressures. The wear behavior of the bainitic steels has been examined in relation to microstructure and the surface damage experienced by the worn rollers. It is considered that such studies could lead to new insights into the wear process itself.