Application of a weakest-link concept to the fatigue limit of the bearing steel SAE 52100 in a bainitic condition

The influence of notches and load conditions on the fatigue limit of the hi gh-strength steel SAE 52100 is investigated. The behaviour can be described quantitatively by a weakest-link concept which describes competitive crack initiation at the surface and at inclusions. This includes the possibility of calculating local and total endurance probabilities depending on the no minal stress amplitude. Crack initiation sites and the fatigue limit can al so be predicted. The basic relation between the size distribution of crack- initiating inclusions and the fracture probability was proved for smooth sp ecimens under tension-compression.