Effects of strain holding on low cycle fatigue behavior of 316 stainless steels in a simulated PWR environments

Abstract

To characterize the effects of strain holding on the fatigue life of austenitic stainless steels in PWR environments, low cycle fatigue life tests were conducted for the type 316 stainless steel in $310 ^\circ C$ air and simulated PWR environments with triangular strain with R ratio = -1. To simulate the actual operating nuclear power plant transient, sub-peak strain holding during the down-hill of strain amplitude was chosen. For 0.4% strain amplitude, a sub-peak holding at 0.36% of strain was decided from the 1st hysteresis loop of fatigue cycles. There are 60 and 300 seconds strain holding condition. Sectioned area observation and TEM analysis were conducted. Overall, no distinct difference on low cycle fatigue life of 316 stainless steel in PWR environments.