Small fatigue crack growth mechanisms of 304 stainless steel under different stress levels

The aim of this paper was to clarify the fatigue crack initiation and small crack growth mechanisms of 304 austenitic stainless steel at different stress levels. Results showed that the stress level effect on small crack growth rates could hardly be distinguished for the stress levels tested. Grain boundaries might act as the crack initiation sites and played an important role on the propagation of small cracks. Once the surface crack length reached the critical size of 0.2 mm, the crack would propagate fairly quickly, resulting in fracture of specimen.