The influence of interacting small defects on the fatigue limits of a pure iron and a bearing steel

This study investigates the effect of interacting small cracks on the fatigue limits of two types of pure iron of varying strengths and of a bearing steel. The experimental results revealed that although the fatigue limits were essentially controlled by the mechanics of interacting cracks, the non-propagating crack features and the severity of crack coalescence varied greatly among the different materials. In addition, it is demonstrated that the material-independent, analytical, interaction-criterion alone is not sufficient to estimate interaction effects in reality. This research shows that the material effect can be considered in terms of hardness and non-propagating crack size.