1000MW超临界电站锅炉包墙过热器爆管原因分析

Analysis of the Cause of Burst Pipe of Wall-wrapped Superheater in 1000 MW Supercritical Power Station Boiler

对某电厂2号机组锅炉的包墙过热器管取样试验,通过宏观检查、力学性能测试及金相组织分析等方法对爆管试样分析和探讨。试验结果表明,包墙过热器爆口呈喇叭状,且减薄、胀粗现象明显,金相组织包括铁素体、珠光体、贝氏体和少量碳化物,推断包墙过热器爆管泄漏的原因为锅炉短时超温运行,而造成这种现象的原因则是高温烟气的不均匀冲刷。最后,为防止类似事故提出了几点建议。

A sample test was taken on the wall-wrapped superheater tube of the No.2 boiler in a power plant.Through macroscopic inspection,mechanical property test and metallographic microstructure analysis method,the burst tube specimen is analyzed and discussed.The test results show that the location of the burst tube of the wallwrapped superheater is horn-shaped,and the thinning and swelling phenomenon in this position are obvious,the metallographic organization includes ferrite,pearlite,bainite and a small amount of carbide,and the results show that the reason for the leakage of the burst tube of the wall-wrapped superheater is that the boiler runs at a short time over-temperature,and the reason for this phenomenon is the uneven flushing of the pipe by high temperature flue gas.Finally,several suggestions were made to prevent the occurrence of the same accident.