Fatigue behavior on weldment of austenitic stainless steel for ITER vacuum vessel

Fatigue test of weldment of 316L stainless steel with an artificial incomplete penetration in weld root was performed to investigate effect of the incomplete penetration on fatigue behavior and fatigue strength. Fatigue crack propagation test of weld metal was also carried out to compare with that of weldment and to evaluate the fatigue lives of weldment based on fracture mechanics. As the results, the incomplete penetration behaved as a crack and most of total fatigue lives for the weldment were crack propagation lives. The crack propagation rates of weldment were in accordance with those of the weld metal. The fatigue strength of the weldment was considerably lower than that of smooth specimen. The effect of incomplete penetration on the fatigue strength of weldment is a serious problem.