某330 MW火力发电厂锅炉水冷壁泄漏原因分析

Cause Analysis of Boiler Water Wall Tube Leakage of a 300 MW Thermal Power Plant

通过宏观分析、磁粉检测、厚度检测、化学成分分析、室温力学性能试验、裂纹形貌及金相组织分析等方法,对某330 MW火力发电厂锅炉2根水冷壁泄漏管样进行了泄漏原因分析,结果表明:泄漏锅炉水冷壁管样打底焊缝与盖面焊缝间存在未熔合缺陷,焊缝存在折口及错边值超标等现象,是导致管子泄漏的直接原因.该管虽然已运行了超10万h,但是因为原始缺陷原因导致泄漏,证明了加强原始焊口无损检测的重要性.

Through macroscopic analysis,magnetic particle testing,thickness detection,chemical composition analysis,room temperature mechanical property test,crack morphology and metallographic analysis,the causes of leakage of two water-cooled wall leakage pipes of a 330MW thermal power plant boiler were analyzed.The results showed that there were an unfused defect between the bottom wall weld and the cover weld of the water-cooled wall tube of the leaking boiler,and the weld seam had the phenomenon that the fold and the misalignment exceed the standard,which was the direct causes of the leakage of the pipe.Although the tube had been in operation for over 100,000 hours,it still leaked due to the original defect,which proved the importance of strengthening the original welding joint nondestructive testing.