水泥窑余热锅炉管屏穿孔失效分析

某水泥窑余热锅炉投运仅两个月,其中压蒸发器最上层管屏弯头处已累计发生了3次穿孔泄漏事故。采用化学成分分析、力学性能测试、宏观分析以及扫描电镜分析等方法,对管屏穿孔失效的原因进行了分析。结果表明：造成管屏穿孔的主要原因是由于该中压蒸发器管屏局部工作介质循环不畅造成管屏弯头处发生气蚀,继而引发冲蚀以及可能伴随的氧腐蚀等一系列减薄行为,它们共同作用造成管屏壁厚不断减薄,最终发生穿孔失效。

Failure Analysis on Perforation of Tube Panel of Cement Kiln Waste Heat Boiler

Perforation leakage accident had happened three times after the tube panel of cement kiln waste heat boiler was put into performance for about two months,and means such as chemical compositions analysis,mechanical property test,macro inspection and scanning electronic microscope observation,were used to analyzed the perforation reasons.The results show that the main reason for the perforation was cavitation erosion happening at the tube panel elbow and caused by non-smooth circulation of local working medium in the middle evaporator.And then washout corrosion and oxygen corrosion were caused by the cavitation erosion,and they acted together and resulted in continuous thinning of the tube panel and final perforation leakage failure.