高温再热蒸汽疏水罐液位计取样管道弯管泄漏原因

Reasons for leakage of sampling pipe elbow of high temperature reheat steam drain tank level gauge

某电厂高温再热蒸汽疏水罐液位计取样管道弯管在运行中发生泄漏。采用宏观观察、化学成分分析、金相检验、硬度测试等方法,对弯管泄漏的原因进行了研究。结果表明:该弯管发生了应力腐蚀开裂,制造弯管时的热处理工艺控制不当,且内壁下部积水提供了腐蚀环境,最终导致弯管发生开裂并泄漏。

The elbow of the sampling pipe for the high temperature reheat steam drain tank level gauge in a power plant leaked during operation.The causes of elbow leakage were studied using macroscopic observation,chemical composition analysis,metallographic examination and hardness testing.The results shows that stress corrosion cracking occurred in the elbow,improper control of the heat treatment process during the manufacturing of the elbow,and accumulation of water at the lower part of the inner wall provided a corrosive environment,ultimately led to cracking and leakage of the elbow.