某200 MW燃煤电厂锅炉水冷壁管在A级检修水压试验过程中发生泄漏。采用宏观观察、拉伸试验、金相检验、扫描电镜及能谱分析等方法,分析了该水冷壁管泄漏的原因。结果表明:因锅炉水质较差、停炉保护不到位、管子传热不良等原因,使富含氧化铁及氧化铜的水渣在锅炉水冷壁管向火面内壁产生沉积,形成垢下氢腐蚀,造成管子强度降低,最终导致管子泄漏。

The water wall tube of boiler in a 200 MW coal-fired power plant leaked during the A-level maintenance hydraulic test.By means of macroscopic observation,tensile test,metallographic inspection,scanning electron microscope and energy spectrum analysis,the reasons for the leakage of water wall tube were analyzed.The results showed that due to the poor water quality of the boiler,the ineffective shutdown protection and the poor heat transfer of the pipe,the water slag rich in iron oxide and copper oxide was deposited on the inner wall of the fire surface of boiler water wall tube,resulting in under-deposit hydrogen corrosion.Caused a reduction in the strength of the pipe,which eventually led to leakage of pipe.