Prolonging fatigue life of a damaged steel by annealing

This paper deals with the endurance life of fatigue failure (defined as a sudden drop of stress range) under constant total strain rate for a quenched and tempered (600 °C for 2 h) steel. The investigation is focused on the effect of annealing at 550 °C for 2 h on the residual fatigue life. Two influencing factors are studied: the fatigue damage degree of the material prior to annealing and the magnitude of the constant total strain amplitude. The total fatigue lives of the specimens with annealing were increased twice as that without annealing. The interpretation of the results is mainly based on TEM observations.