Role of mean stress on fatigue behavior of a 316L austenitic stainless steel in LWR and air environments

Mean stress effects on fatigue life of a stainless steel in air and boiling water reactor (BWR) environments were evaluated by load-controlled tests. In stress-life, non-zero mean stresses increase life in low cycle fatigue regime in both environments and in high cycle regime in air. In high cycle fatigue regime in BWR environment, higher fatigue life was observed with negative mean stress while a decrease of the fatigue limit was found for positive one. In strain-life, the mean stress effects are insignificant. All data are well correlated with a Smith-Watson-Topper parameter showing no interaction between mean stress and BWR environment.

Automated summary

The study found that stress has different effects on fatigue life in air and BWR environments. In the high cycle fatigue regime, negative mean stress is beneficial for increasing fatigue life, while positive mean stress may result in a decrease of the fatigue limit. The effects of mean stress are insignificant in strain-life.