除氧器蒸汽斜管管座裂纹失效分析

Failure analysis of crack in header of deaerator's steam inclined tube

通过失效焊缝断口形貌观察,材料成分、组织及力学性能测试,并结合蒸汽斜管和管座焊缝的运行工况和应力分布,系统研究了除氧器蒸汽斜管管座焊缝的失效原因。结果表明,焊缝处的焊接缺陷在外界环境、运行应力的共同作用下发生应力集中,造成缺陷处疲劳裂纹萌生和扩展,导致疲劳断裂。因此,工程实际中应加强焊接质量的控制、定期进行管道焊缝的无损检验,可减少后续失效的发生。

By testing the failure of weld fracture morphology, material composition, microstructure and mechanical properties, also combined with the operating conditions and stress distribution of steam inclined pipe and tube socket weld, it was studied that the weld failure of deaerator's steam chute seat. The results showed that the main reason for failure was stress concentration in the welding defects of weld by the action of external environment and operational stress, causing the initiation and propagation of fatigue crack in defects, finally leading to fatigue fracture. Therefore,it should be controlled that the quality of welding strengthenly in the actual project and test the pipe welds by nondestructive regularly, thus the incidence of subsequent failures would be reduced.