Life prediction of creep-fatigue for 304H with welded joints

Butt weld joints of 304H stainless steel were divided into three: ones without change, ones eliminated stress by ultrasonic and others with solution treatment, respectively. Three kinds of butt weld joints were conducted fatigue-creep experiments at 680 °C. The results showed that the ultrasonic treatment cannot improve the life of failure, solution treatment can significantly improve the life of failure, and the life of failure through the solution treatment was about 1.6 times of the life of as-welded. At the same time, the life prediction formulas of creep-fatigue for butt weld joints of 304H stainless steel at 680 °C were established according to four kinds of creep-fatigue life prediction models. Prediction effects of four kinds of life prediction models were compared in descending order, ductility depletion method, the average strain rate method, strain energy frequency separation, ductility exhaustion and damage mechanics method for their prediction accuracy.