A Novel Method for the Prediction of Critical Inclusion Size Leading to Fatigue Failure

The fatigue behavior of two commercial 30MnVS6 steels with similar microstructure and mechanical properties containing inclusions of different sizes were studied in the 10 7 cycles fatigue regime. The scanning electron microscopy (SEM) investigations of the fracture surfaces revealed that the nonmetallic inclusions are the main sources of fatigue crack initiation. Calculated according to the Murakami’s model, the stress intensity factors were found to be suitable for the assessment of fatigue behavior. In this article, a new method is proposed for the prediction of the critical inclusion size, using Murakami’s model. According to this method, a critical stress intensity factor was determined for the estimation of the critical inclusion size causing the fatigue failure.