某锅炉内大量对流管出现表面腐蚀及泄漏情况。通过宏微观腐蚀形貌分析、金相分析、化学成分分析及力学性能测试，并结合现场的实际运行情况，分析了对流管失效的原因。结果表明：对流管材料的各项性能均正常；引起对流管泄漏的主要原因是管道在冷凝水中发生氧腐蚀穿孔，冷凝水中存在腐蚀性离子（氯、硫酸根等），腐蚀点处会吸附这些离子，导致周围钝化膜破坏，加速电化学腐蚀，最后形成贯穿性孔洞，使对流管发生蒸汽泄漏。

Surface corrosion and leakage occurred on a large number of convection pipes in a boiler. Based on macro and micro corrosion morphology analysis, metallographic analysis, chemical composition analysis, and mechanical property testing, combined with the actual operating conditions on site, the causes of convection pipe failure were analyzed. The results show that the properties of convection pipe material were normal. The main cause of leakage of the convection pipes was that the pipes were perforated by oxygen corrosion in condensed water. There were corrosive ions (chloride, sulfate, etc.) in the condensed water, these ions were absorbed at corrosion points, causing the destruction of the surrounding passivation film and accelerating electrochemical corrosion. Finally, penetrating holes were formed and steam leakage occured in the convection pipes.