【摘要】 某超临界机组用20Cr1Mo1VNbTiB钢高温螺栓出现了早期断裂，对断裂的宏观和微观特征进行了观察，分析了螺栓老化状况，探讨其失效原因。结果表明，20Cr1Mo1VNbTiB钢螺栓经高温运行后，碳化物聚集长大不明显，抗拉强度和硬度没有明显下降，但冲击性能明显降低，可见螺栓断裂失效与老化无关。装配时的预紧力过大，加速了螺栓的蠕变损伤，根据断口形貌判定其断裂性质为高温蠕变断裂。更多还原

【Abstract】 A high-temperature bolt made of 20Cr1Mo1VNbTiB steel for a certain supercritical unit was early fractured. The macroscopic and microscopic characteristics of the fracture were observed, the aging condition of the bolt was analyzed, and the failure reasons were discussed. The results show that after running at high temperature, the aggregate growth of carbides in the bolt is not obvious, the decrease of tensile strength and hardness is not significant, but the decrease of impact absorbed energy is obvious, which means that the bolt fracture failure is not related to the aging. Excessive preload during the bolt assembly accelerates its creep damage. According to the fracture morphology, it is determined that the fracture belongs to high temperature creep rupture.更多还原