通过宏观检验、化学成分分析、力学性能试验、金相检验、扫描电镜以及能谱分析等方法，对某锅炉水冷壁内螺纹管在运行过程中发生泄漏的原因进行了分析。结果表明：在锅炉机组启停炉或负荷变化期间，该水冷壁内螺纹管向火侧温度波动较大，使其承受较大的交变热应力，诱发管壁产生横向热疲劳裂纹，同时管壁附着的含硫腐蚀性灰分结焦，也对裂纹的扩展具有促进作用，两者共同作用造成该水冷壁内螺纹管发生泄漏失效。

The leakage reasons of the internally ribbed tube in a boiler water wall during operation were analyzed by methods of macroscopic examination, chemical composition analysis, mechanical property test, metallographic examination, scanning electron microscope and energy spectrum analysis and so on. The results show that during the period of start-up, shutdown or load change of the boiler unit, due to the large temperature fluctuation, the internally ribbed tube wall on the fire-facing side would withstand a large alternating thermal stress, which resulted in transversal fatigue cracks appearing in the tube wall. At the same time, the corrosive ash containing sulfur which attached to the tube wall promoted the expansion of the cracks. The above two factors co-acted and caused the leakage of the internally ribbed tube in the water wall.