余热锅炉受热面管泄漏失效分析

Failure Analysis on Leakage of Heating Surface Tubes of Waste Heat Boilers

某燃气机组2台余热锅炉的部分受热面管在试运行过程中发生泄漏,通过宏观观察、化学成分分析、力学性能测试、金相检验、扫描电镜及能谱分析、X射线衍射等方法对管子泄漏原因进行了分析。结果表明:发生泄漏管子的内壁具有较多的腐蚀产物,经分析为铁的氧化物,腐蚀产物的组成以及腐蚀坑的形貌均说明管子内壁发生了局部氧腐蚀,腐蚀部位变薄形成凹坑,严重处发生了穿孔泄漏。

Partial heating surface tubes of two waste heat boilers in a gas power unit leaked during the trial operation.The causes of tube leakage were analyzed by means of macroscopical observation,chemical composition analysis,mechanical property test,metallographic examination,scanning electron microscope,energy spectrum analysis and X ray diffraction.The results show that there were more corrosion products on the inner wall of the leakage tubes,and the corrosion products were the oxides of iron.The composition of the corrosion products and the morphology of the corrosion pit indicate that local oxygen corrosion had occurred on the inner wall of the tubes.The corrosion part became thinner and the pit was formed,and the perforation and leakage occured in the serious corrosion.