某电厂循环流化床锅炉用15CrMoG钢高温过热器在服役22 000 h后的水压试验中发生泄漏。采用宏观检查、化学成分分析、硬度试验、金相检验、扫描电镜与能谱分析等方法对其泄漏原因进行了分析。同时，提出了相应的改进措施。结果表明：高温过热器管内电化学腐蚀和管外烟气腐蚀共同作用造成壁厚严重减薄，最终导致管道泄漏。

A high temperature super-heater of 15CrMoG steel used in a circulating fluidized bed boiler of a power plant leaked during the hydrostatic test after 22 000 h of service. Macro examination, chemical composition analysis, hardness measurement, metallographic examination, scanning electron microscopy and energy dispersive spectroscopy were conducted for analyzing the leakage causes of the super-heater. And corresponding improvement measures were proposed. The results show that the cooperation of electrochemical corrosion in the pipes of the high-temperature super-heater and flue gas corrosion outside the pipes caused a serious reduction in wall thickness, which eventually led to the leakage of pipes.