304H焊接接头蠕变疲劳寿命预测

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

文中进行了温度680℃,具有保持时间的304H对接焊试样在超声波消应力、焊态固溶处理状态下的蠕变疲劳试验.结果表明,超声波消应力处理不能改善失效寿命,固溶处理可以显著提高失效寿命,固溶处理失效寿命约为焊态的1.6倍,同时根据四种蠕变疲劳寿命预估模型建立了680℃304H不锈钢焊态蠕变疲劳寿命预估式,并对四种寿命模型寿命预测效果进行了比较,其精度由高到低依次是延性耗竭法、平均应变速率法、应变能频率分离法、延性耗竭与损伤力学法.

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.