锅炉高温过热器管爆裂失效分析

Failure Analysis on High Temperature Superheater Tube Crack of Power Plant Boiler

对电厂锅炉高温过热器管爆裂样管进行宏观形貌分析、化学成分分析、金相组织检验及力学性能检测。结果表明,钢的化学成分符合标准要求,室温力学性能强度满足标准要求而塑性低于标准要求;珠光体出现球化,在晶界处有聚集碳化物颗粒析出,晶界已形成微裂纹,爆口附近出现蠕变孔洞;烟气腐蚀冲刷减薄管壁,造成高温过热器管在弯头外侧的开裂。建议加强对高温过热器管金属工作温度的监测,同时采取合理的防磨措施,以减少烟气对高温过热器管外壁的腐蚀冲刷。

The macro-analysis, chemical composition analysis, microstructure examination and mechanical property test of high temperature superheater tube in power plant boiler were carried out. The results show that the chemical composition of the steel conforms to the standard requirement. The room temperature strength meets the standard requirements and plasticity below standard requirements. The pearlite spheroidization and the gathered carbide particle precipitate in the grain boundary.The grain boundary has micro-crack formation and creep holes appear near open seam. Flue gas erosion reduction of thin wall results in the outside of the bend craze of high temperature superheater tube. The corrosion erosion reduces from the flue gas into high temperature superheater tube outer wall, strengthen monitoring of high temperature superheater tube metal temperature and taking reasonable measures to against erosion-corrosion at the same time are suggested.