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通过拉伸试验、弯曲试验、冲击试验和高温持久试验,并采用扫描电镜对冲击断口进行形貌观察,研究了X20CrMoV12.1钢焊接接头运行165000 h后的性能变化。结果表明:经过长时高温运行后其焊接接头出现了显著的时效脆化现象,冲击断口为典型的脆性断裂状态;运行后接头仍具有足够的塑性,并且接头的强度高于母材,但接头和母材的伸长率和断面收缩率远低于初始状态。综合高温持久试验结果,建议下一个大修期进一步对管道进行寿命评估。
The tensile test, bending test, impact test and long-term high temperature test were carried out. The morphology of impact fracture was observed by scanning electron microscope. The performance of X20CrMoV12.1 steel welded joint after 165000 h operation was studied. The results show that there is a significant age-induced embrittlement of the welded joint after long-time high temperature operation, the impact fracture is a typical brittle fracture state; the joint still has enough plasticity after operation and the strength of the joint is higher than that of the base metal, And base metal elongation and reduction of area much lower than the initial state. Based on the results of the long-term high-temperature test, it is suggested that the life span of the pipeline be further evaluated in the next overhaul period.