火电机组锅炉水冷壁管泄漏原因

Reasons for leakage of boiler water cooled wall pipe in thermal power units

某电厂锅炉水冷壁管发生泄漏事故,造成机组停运。采用宏观观察、化学成分分析、力学性能测试、金相检验、扫描电镜分析、外径及壁厚测量等方法分析了水冷壁管泄漏的原因。结果表明:水冷壁管鳍片切口端部及根部外形尖锐且未进行圆滑过渡,在该处产生了应力集中,锅炉在运行过程中受到交变应力以及结构松动导致的振动作用,应力集中处萌生了裂纹并不断扩展,最终导致水冷壁管发生泄漏。

A leakage occurred in the water cooled wall pipe of a power plant boiler,causing the unit to shut down.The reasons for the leakage of water cooled wall pipes were analyzed using methods such as macroscopic observation,chemical composition analysis,mechanical property testing,metallographic examination,scanning electron microscopy analysis,outer diameter and wall thickness measurement.The results show that the end and root of the fin notch of the water cooled wall tube had a sharp shape and did not undergo a smooth transition.Stress concentration occurred at this point,and the boiler was subjected to alternating stress and vibration caused by structural loosening during operation.Cracks initiated and continued to expand at the stress concentration point,ultimately led to leakage of the water cooled wall tube.