某电厂水冷壁管冷灰斗角焊缝泄漏原因分析

某电厂2#炉在运行过程中发现水冷壁下部冷灰斗角焊缝处出现一处泄漏。对出现泄漏的样管开展化学成分分析、力学性能、宏观检查及金相分析。试验结果及分析表明,角焊缝存在带明显尖角的夹渣焊接缺陷,在焊接应力下产生裂纹,裂纹在锅炉运行过程中向管子内壁扩展,并形成贯穿型裂纹,导致发生蒸汽泄漏。

During the operation of the furnace in a power plant,a leakage was found at the corner weld of the cold ash bucket at the lower part of the water wall.Chemical composition analysis,mechanical properties,macroscopic inspection and metallographic analysis were carried out on the leaked sample tube.The test results and analysis show that there is a slag welding defect with obvious sharp angle in the fillet weld,which produces cracks under welding stress,and the cracks propagate to the inner wall of the pipe during the operation of the boiler,and form penetrating cracks,thus resulting in steam leakage.