电厂水冷壁管开裂分析

Cracking Analysis on Water Cooling Wall Pipe in Power Plant

对开裂的电厂水冷壁管进行了化学成分及金相组织分析,并对断口进行了扫描电镜分析。结果表明,水冷管壁开裂原因是由于在鳍板与管子焊缝端头存有较大的应力,组织中有夹杂物存在,在工作压力作用下,裂纹在焊缝端头处萌生并沿拉应力区扩展,最后造成宏观脆性断裂。

The microstructure and chemical composition of cracked water-cooling wall pipe used in power plant were analyzed, and its fracture was analyzed by SEM. The result shows that there are residual stress and inclusions in the structure at weld end between pipe and fin plate, and under working pressure the cracks initiate in weld end, then they propagate along tensile stress area and eventually result in fracture.