Low cycle fatigue behaviour of a medium carbon microalloyed steel

Abstract

Room temperature low cycle fatigue (LCF) and fracture behaviour of a medium carbon V-bearing microalloyed steel has been studied. The experimentally determined LCF life is compared with the life predicted by the ‘modified universal slopes’ equation. Cyclic stress response showed softening at lower plastic strain amplitudes (≤0.3%) and hardening at higher plastic strain amplitudes (>0.3%). The possible reasons for the above behaviour are discussed. An analysis of the fracture surfaces revealed a mixed mode of fracture that involved different fracture mechanisms. Cracks did not initiate at the inclusions.