高温再热器管失效研究与对策

Failure Research and Countermeasures for Temperature Reheat Tube

对锅炉再热器管进行宏观检查、化学成分分析、金相显微组织观察和力学性能测试,分析了锅炉再热器管的失效原因。结果表明:该锅炉二级再热器管由于超温运行,因过热引起管子弯头的内外壁产生较厚的氧化皮。管子外弧面壁厚不足并在高温作用下使该处管子发生局部鼓胀,致使氧化皮开裂,露出的基体金属继续被氧化,管子内表面不断氧化与膨胀,导致锅炉二级再热器管破裂。

The macroscopic examination, chemical composition analysis, observation of microstructure and analysis of mechanical properties of boiler reheater tubes were carried out. The reasons for the failure of the tubes were researched. The results show that due to the over-temperature operation of boiler secondary reheater tube, the inner and outer wall of the tube bends produces thicker oxide due to the overheating. The outer arc tube wall thickness and insufficient under high temperature can make the pipe bulge locally, which can result in the crack of the scale.The exposed metal base continues to be oxidized, which are constantly subjected to oxidation and expansion of inner surface of the tube, resulting in the crack of secondary reheater tube of boiler.