10号钢U型换热管的泄漏原因

Failure Reason of U-type Heat Exchanger Tube Made of 10~# Steel

采用宏观形貌观察、化学成分分析、腐蚀产物能谱及X衍射分析、显微组织检查等,对某厂运行约半年即泄漏的10号钢U型换热管进行了失效原因分析。结果表明:U型管外壁结垢严重,发生了垢下腐蚀;同时,Cl^-在垢下闭塞区中富集并引发"自催化酸化"效应,加速了垢下腐蚀的进程,导致换热管半年内就发生泄漏。

Macroscopic morphology observation, chemical composition analysis,corrosion product energy spectrum and X-ray diffraction analysis and microstructure inspection were used to analyze the failure reasons of a 10~# steel Ushaped heat exchange tube run in a plant for about half a year. The results show that the fouling on the outer wall of the U-tube was serious and the corrosion under the scale occurred. At the same time, the enrichment of Cl-in the occlusion zone under the scale and the "autocatalytic acidification" effect accelerated the progress of corrosion under the scale, resulting in leakage of the heat exchange tube within half a year.