Effects of non-metallic inclusions on the crack propagation in bearing steel

The crack propagation in bearing steel with a non-metallic inclusion is analyzed by Voronoi finite element method. The load applied on the Voronoi finite element model is obtained by combination of quasi-dynamic method and Hertzian contact theory. Von Mises stress distribution in the micro-domain is calculated to determine the crack initiation. The result shows that the non-metallic inclusion acts as stress raiser and the maximum von Mises stress appears near the inclusion. Thus, we can conclude that the crack is initiated near the inclusion. Stress intensity factors (SIFs) were calculated to study the crack propagation as a function of inclusion elastic modulus, size, and depth. The crack is more likely to grow when the inclusion is soft, small and shallow.