Rolling contact fatigue characteristics of newly developed bearing steel with addition of Si and Mo under quasi-high temperature

In order to elucidate the rolling contact fatigue characteristics of the newly developed bearing steel SBS1 principally under the quasi-high temperature, the washer and ball specimens made of SBS1 were tested at a temperature of 403 K and also at non-controlled temperatures under a rolling contact condition using a thrust bearing type rolling fatigue testing machine. This kind of test was performed also by using the conventional bearing steel SUJ2 for the comparison. For discussing these results about the rolling contact fatigue lives of the washers, the microstructural changes of the fatigue-tested washers and balls were observed around the depth where the orthogonal shear stress and the maximum shear stress become maximum. The soaking test was also conducted at a temperature of 453 K using the balls, and the changes of the hardness and the full width at half maximum with the increase of the soaking time was examined. It could be clarified from these investigations that the rolling contact fatigue life of the newly developed bearing steel SBS1 was much longer than that of the conventional bearing steel SUJ2 especially under the quasi-high temperature.