OS0821 Influence of loading conditions and surface roughness on the low cycle fatigue life of austenitic stainless steel in high temperature water
Details
NUREG/CR-6909 of USA and JSME S NF1 of Japan proposed new rules for evaluating environmental effects in fatigue analyses of reactors components. These rules were established from a lot of fatigue data with polished specimens under simple loading condition. The effects of surface finish or complex loading condition were reported in some papers, but these data were obtained with the simple shaped specimens. In order to evaluate the effects of surface finish and loading condition and to confirm the applicability of the proposed rules to actual components, Low Cycle Fatigue tests are performed with the specimens cut from 316 austenitic stainless steel welded piping in PWR environment. The pipes are machined to have three levels of surface finish condition and the load pattern simulating to thermal stress is loaded to specimens. In this study, the effect of surface finish on fatigue life is small for 316 austenitic stainless steel welded piping. Considering the insensitive region in the current evaluation rule, predicted accuracy is increased and possibility of improving the current rule is indicated.
