Study on Creep Rupture Strength of Friction Welded Super304H Steel Weld Joints

Abstract

In this paper, the creep rupture strength for Super304H weld joints was evaluated by isothermal method. Service life prediction curves indicate that Super304H weld joints could guarante safety service for 105 hours at 625°C, which is in according with the Ultra-supercritical units steam conditions. When the stress is higher, the rupture mode of creep specimens was transcrystalline fracture, and results in forming dimples. When the stress is lower, the rupture mode of creep specimens was creep rupture, and results in cleavage rupture. So under the effect of long term low stress, creep cavities joined each other along the grain boundary.