电站锅炉过热器管爆管分析

Analysis of Superheater Tube Bursting in Power Plant Boiler

通过宏观分析、化学成分分析、硬度试验、拉伸试验、金相及扫描电镜分析等方法对T91高温过热器管爆管原因进行分析。结果表明:钢管向火侧强度和硬度下降明显,钢管爆口附近晶粒变形严重、晶界处有大量碳化物析出、有宏观蠕变裂纹出现,说明爆管是由于长期过热导致钢管力学性能劣化和微观组织老化、损伤所致。

The causes of leading to T91 high temperature superheater tube burst failures were analyzed by means of macro examination, chemical composition analysis, hardness test, tensile test, metallographic structure analysis, SEM and so on. The experimental results showed that the strength and hardness of tube exposing to fire decreased obviously, the grain deformation near the burst of the tube was serious, a large number of carbides precipitated at the grain boundary, and macroscopic creep cracks appeared near the burst of tube. These results indicated that the tube burst was caused by the deterioration of mechanical properties and the aging and damage of micro-structure caused by long-term overheating.