Effects of inclusion size and stress ratio on fatigue strength for high-strength steels with fish-eye mode failure

Experimental results indicate that the fatigue life reduces by about two orders of magnitude when inclusion size doubles. Then, a model is proposed for predicting the fatigue strength of high-strength steels with fish-eye mode failure based on the experimental results for the effect of inclusion size and stress ratio. In the model, the effect of inclusion size a0 and stress ratio R on fatigue strength σa is expressed as σa ∝ a0m[(1 − R)/2]α, where m and α are material parameters. The predicted results are in good agreement with our experimental results and the ones reported in literature.