华电技术 ›› 2018, Vol. 40 ›› Issue (10): 27-29.

• 技术交流 • 上一篇    下一篇

20Cr1Mo1VNbTiB高温螺栓断裂失效分析

  

  1. 1.广东电研锅炉压力容器检验中心有限公司,广州〓510700;  2.东风天汽模(武汉)金属材料成型有限公司,武汉〓430040
  • 出版日期:2018-11-26 发布日期:2018-12-13

Failure analysis of 20Cr1Mo1VNbTiB hightemperature bolt

  1. 1.Guangdong Dianyan Boiler Pressure Vessel Inspection Center Company Limited, Guangzhou 510700, China; 2.Dongfeng TQM (Wuhan) Metal Forming Company Limited, Wuhan 430040, China
  • Online:2018-11-26 Published:2018-12-13

摘要:

对某电厂汽轮机进行解体检修,发现1根材质为20Cr1Mo1VNbTiB的高温螺栓已断裂。采用断口分析、金相试验、常温力学性能试验及化学成分分析法分析其断裂原因。结果表明,螺杆表面密集的机械损伤所引起的应力集中是导致此次螺栓发生断裂的直接原因;同时,螺栓晶粒较粗大、碳化物在长期高温高压运行过程中析出、冲击韧性下降是螺栓发生解理脆性断裂的根本原因。

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Abstract:

In a dismantling repairmen of a steam turbine of a power plant, a hightemperature bolt made of 20Cr1Mo1VNbTiB was found broken. The fracture causes were analyzed by fracture analysis, metallographic test, mechanical properties test at room temperature and chemical composition analysis. The results show that the stress concentration caused by the mechanical damage on the screw surface is the direct cause of the bolt breakage. At the same time, coarse crystal grain of bolt, the carbide precipitating under longterm high temperature/highpressure operation, and reduce of  impact toughness  are the root causes of cleavage brittle fracture of the bolt.

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