Fatigue Fracture of Duplex Stainless Steel with Heterogeneous Nanostructure by Heavy Cold Rolling

Abstract

Fatigue behaviors of duplex stainless steels with excellent tensile properties brought by heterogeneous nanostructure were examined with changing volume fraction of ferritic-austenitic phases. In as-rolled samples, fatigue strength taken by 10⁷ cycles became double comparing with those of conventional stainless steels. The volume fraction of ferritic-austenitic phases has not affected fatigue behavior. Further, the fatigue strength was improved additionally 200 MPa by aging heat-treatment after cold rolling. The duplex stainless steels with heterogeneous nanostructure possessed enough fatigue strength even in 3%NaCl solution though its fatigue strength declined.