火电厂锅炉水冷壁管横向裂纹开裂原因分析

Failure Analysis on Water Wall Tube Transversal Crack of Power Plant Boiler

对电厂锅炉水冷壁管与鳍板焊接处开裂原因进行失效分析。结果表明:水冷壁管向火一侧表面氧化严重,管内侧存在结垢现象,同时水冷壁管珠光体发生球化,在运行过程中,在循环热应力和焊接残余应力叠加作用下,裂纹在焊缝接头处萌生,沿着拉应力区扩展,造成疲劳开裂。

The crack reason of the water wall tube in power plant boiler which attached to the welding with the fin tube wall was analyzed.The results show that superficial oxidation takes place on the appearance of water wall tube,typical scaling scale exists on the internal surface and partial pearlite is spheroidized.Cracks initiate in areas with attachment weld,leading to the explosion of the water wall tube in the boiler due to the cycle thermal stress and welding stress.