Low Cycle Fatigue Behavior of 316L Stainless Steel Thin Sheets

摘要

In this paper, tension-tension fatigue test were conducted to investigate the fatigue properties of 316L Stainless Steel thin sheets by using a micro mechanical fatigue testing system at room temperature. The effect factors including thickness, loading frequency and stress ratio were considered. The results show the S-N curve of the thin sheets descends continuously in low cycle regime. Cyclic σ-N curve and s-N curve were obtained according to the traditional fatigue theory. The results agree well with the experimental fatigue data, showing that the traditional fatigue research methods would also be suitable to describe the thin sheets in a certain extent. The fatigue behavior of thin sheets is much better than that of plates, showing great size effect, and the fatigue strength is increased with the decrease of thickness. With the increase of loading frequency or loading stress ratio, the fatigue strength of thin sheets is increased. The fracture surfaces of fractured sheets were investigated with scanning electron microscopy (SEM). It shows fatigue failure initiates from inclusions or defects on the specimen surface.