LAUSR

Abstract This paper presents the influence of different pre-straining paths on the notch fatigue performance of Dual Phase 600 steel. Initially, pre-straining is done in rolling (or transverse) direction. Then tensile and notch fatigue specimens are fabricated in parallel to the initial pre-straining direction i.e. in rolling (or transverse) direction. In another case, the tensile and notch fatigue specimens are fabricated in orthogonal to the initial pre-straining direction i.e. initial pre-straining in  rolling (or transverse) direction, and followed by testing in transverse (or rolling) direction. Tensile and notch fatigue performance has been evaluated for the as-rolled and uniaxial pre-strained specimens having different pre-straining paths. A huge reduction in notch fatigue life is noticed as compared to fatigue performance on smooth samples due to the existence of stress concentration at the notch root. Pre-straining has no significant effect on notch fatigue performance, while a considerable improvement of high cycle fatigue performance is observed for smooth specimens. Finite element analysis suggests that stress concentration at the notch root increases and plastically deformed zone reduces with the pre-straining. At the same time, tensile yield stress and endurance limit rise with pre-straining for the smooth specimens. An increase in stress concentration due to pre-straining nullifies the enhancement of tensile yield stress and endurance limit for the notched specimen.