Effects of 100 ppb dissolved oxygen on low-cycle fatigue behaviors of 316LN austenitic stainless steel in borated and lithiated high temperature water and mechanism behind these effects

In this work, beneficial effects of dissolved oxygen (DO) on the crack initiation and propagation in borated and lithiated high temperature water were observed, which finally increased the low-cycle fatigue (LCF) life of the 316LN in the water. The 100 ppb DO added in the water also reduced the total amount of absorbed hydrogen. Meanwhile, the oxide film formed was more protective compared with the oxide films formed in oxygen free water. Based on the metallurgical and electrochemical characterizations conducted in the present study, a scheme of the mechanism of the LCF life increase is proposed.