Fracture mechanics approach to initiation of subsurface cracks of carburized SCM415 under rolling contact fatigue

Abstract

Recently it has been shown that the threshold values of SIFs are important in order to evaluate fatigue limits of hard materials. And so we can recognize that the causes of the fatigue are small cracks and inclusions, and that the fatigue limits are more affected by the critical values of SIFs than the values of stresses. In the present work the rolling contact fatigue tests of carburized SCM415 were carried out and the S-N datum of its long-range life were obtained. Flaking failure was observed, and the crack initiation behavior was investigated in terms of fracture mechanics.