Effect of heat and mechanical surface treatments on the fatigue properties of SAE 8620 steel

In this study, the fatigue properties of SAE 8620 case hardened steel was investigated. Carburizing, shot peening and their combinations were applied to SAE 8620 steel fatigue specimens. Different fabrication parameters of carburizing were applied. Shot peening was also applied to carburized and non carburized specimens. Hardness and residual distribution of mechanical and heat-treated fatigue specimens were determined. Rotating bending fatigue tests were performed using treated test specimens. Plotted S-N curves, for treated at different conditions and different ways, were compared to curves for drawn specimens. The maximum increase in fatigue limit is determined for double quenched and shot peened specimens as 72%. (author)