Cracks between the inclusion and the matrix metal are major defects affecting the forgings' fatigue life and impact properties. In hot forging processes, the stress field around a brittle inclusion is one of the most important factors for crack coalescence. In order to study the stress field's influence on crack initiation, the definition of average relative spherical stress(ARSS)and its mathematical expression are given. Influences of ARSSes of various stress fields on matrix metal-brittle inclusion crack ...