<title>Effect of mean stress and residual stress on fatigue strength improvement of ferritic stainless steel</title>

Abstract

This paper covers investigations of the effect of compressive mean stress on fatigue properties of non-deformed specimens and the effect of compressive residual stress on fatigue properties of plastically deformed specimens of ferritic stainless steel by roller-working. Tensile-compressive fatigue test and rotating banding fatigue test have been performed on these specimens. The results showed that according to increase of the compressive mean stress the fatigue strengths of these specimens increase. Compressive mean stress delays crack initiation and suppresses fatigue crack propagation properties. In case of tensile mean stress, this kind of mean stress decreases the fatigue strength. The fatigue limits of plastically deformed specimen are much higher than that of non-deformed specimen and does not linearly increase with an increase of plastic deformation value. The fatigue limit improvement of deformed specimens would be caused by notch root compressive residual stress and work-hardening due to roller working.