Abstract：Using four-point bending fatigue test studied the fatigue behavior of nickel free high nitrogen stainless steel in different stress levels， and the micro morphology， initiation position and propagation trace of fatigue crack were analyzed. The fracture of experimental steel was multiple cracks， and the total crack length increased gradually with the increase of stress level. The crack length tends to be stable when the stress level was close to the yield limit of the material. Most of the cracks initiated at the slip zone， and the crack were distorted， migrated and bifurcated in the process of crack propagation. The crack propagated mainly along single slip band or multiple slip bands in the grain and deflected when crack crossed the grain boundary or twin boundary.
2017, Vol. 52 
