Abstract
This paper describes the notch fatigue behaviour of a 316 stainless steel hardened by carburizing. Fatigue tests were performed using cantilever-type rotary bending fatigue testing machines in laboratory air at ambient temperature. Notched specimens with three different stress concentration factors (α=2.08, 3.55 and 6.50) were evaluated. All carburized notched specimens showed higher fatigue strength than the untreated ones and the increase in fatigue strength decreased with increasing stress concentration factor. Fatigue cracks initiated at the surface of the notch root at higher applied stresses, while subsurface at lower applied stresses in the carburized notched specimens with α=2.08 and 3.55, but surface regardless of stress level in the carburized notched specimens with α=6.50. Both untreated and carburized materials indicated a significantly low notch sensitivity, but the notch sensitivity was enhanced slightly by carburizing.
