某电厂超超临界清洁高效燃煤发电机组锅炉钢管发生泄漏。采用宏观检查、化学成分分析、拉伸试验、硬度测试及金相检验等方法对钢管泄漏原因进行了分析。结果表明：末级过热器钢管因被异物堵塞而处于超温运行状态，使钢管的力学性能劣化，进而导致钢管的承压能力下降，在内压应力作用下，钢管的蠕变速率加快，其表面萌生出蠕变裂纹，最终导致钢管发生泄漏。

The boiler steel pipe of a ultra supercritical clean and efficient coal-fired power plant leaked. The leakage causes of steel pipe were analyzed by means of macroscopic examination, chemical composition analysis, tensile test, hardness test and metallographic examination. The results show that steel pipe of the final superheater was in the state of overheating operation because it was blocked by foreign matters, which led to the deterioration of the mechanical properties of steel pipe, and then caused the decrease of the pressure bearing capacity of steel pipe. Under the action of internal pressure stress, the creep rate of steel pipe accelerated, and the creep cracks were generated on its surface, resulted in the leakage of steel pipe.