S30432奥氏体不锈钢管后屏过热器爆管原因分析

Analysis of Causes for Tube Burst of S30432 Austenitic Stainless Rear Platen Superheater

针对某电厂660MW超超临界机组后屏过热器爆管试样进行化学成分分析、力学性能测试、金相分析和宏观形貌分析。试验结果表明,爆管是由于后屏过热器S30432奥氏体不锈钢管管段处于长期超温运行状态,导致钢管产生蠕变孔洞进而形成许多微观裂纹。当停炉检修启炉后满负荷运行时,由于高温高压的作用使微观裂纹迅速扩展而导致爆管。

Studding on the burst samples of rear platen superheater of 600MW Ultra Supercritical U- nit of a Power Plant, did the chemical analysis, mechanical property test, metallographic analysis and macro analysis. The experimental results showed that, the S30432 austenitic stainless steel tube of rear platen superheater in long - term over temperature operation state cause steel tube generate creep holes, then form many micro cracks. When the boiler full load operation after overhaul, the tube burst because of the high temperature and high pressure make the micro cracks rapidly expanding.