Influence of crowning on rolling contact fatigue of steel rollers

The rolling contact fatigue of crowned rollers made of bearing steel was investigated with a two-roller test machine under a sliding-rolling contact condition with oil lubricant. The nominal crowning radii of the rollers were 110, 90 and 60 mm. The roller was mated with a non-crowned roller or a roller with a concave crowning radius of 110 mm. In case that no edge load or minor edge load occurred, the failure mode of the rollers tended to be pitting caused by surface cracking and the rolling contact fatigue strength evaluated with the normal load increased with increasing crowning radius. In case that the edge load was great, the failure mode of the rollers tended to be spelling caused by subsurface cracking and the difference in the rolling contact fatigue strength was little.