Dependence of the cyclic stress–strain curve on loading history and its interaction with fatigue of 304L stainless steel

This study investigates the effects of loading history on the cyclic stress–strain curve and fatigue behavior of 304L stainless steel at room temperature. Tension–compression tests were performed on the same specimen under controlled strain, using several loading sequences of increasing or decreasing amplitude. The results show that the cyclic curve is not unique, as it depends on the loading sequence. The same predeformed specimens were subjected to fatigue tests. The results showed that fatigue life is significantly reduced by the previous loading history. A previously developed method for determining the effect of prehardening was evaluated. Microstructural analyses were also performed; the microstructures after preloading and their evolution during the fatigue cycles were characterized by transmission electron microscopy (TEM). The results of these analyses improve our understanding of the macroscopic properties of 304L stainless steel and can help us identify the causes of failure and lifetime reduction.

► Contrary to low deformation, cyclic curve is not unique at high strain amplitude.
► However, as the loading was continued cyclic hardening tends to stabilize.
► Cyclic hardening is mainly kinematic type, isotropic component remains quasi-linear.
► Increasing in pre-hardening strain amplitude has almost no effect on fatigue damage.
► Fatigue life decreasing is associated with formation of walls, cells and defect bands.