Analysis of the Cause of Corrosion and Perforation of Fin Tube for Boiler
Author of the article:DONG Xuejiao
Author's Workplace：Pangang Group Research Institute Co.,Ltd.,State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization,Panzhihua 617000,China
Key Words：finned tube perforation thermal fatigue high-temperature corrosion
Abstract：The reason of perforation of finned tube used in boiler was analyzed by chemical composition analysis,metallographic analysis and SEM.The results show that the thickness of the side wall of the finned tube is severely reduced,indicating that the local aerodynamic field of the boiler is not good,which leads to the repeated scouring of the burning flame on the side of the finned tube to the fire,resulting in the change of thermal stress,and the corrosive thermal fatigue on the side of the finned tube to the fire.The free sulfur can directly penetrate through the metal surface protective film of the pipe wall and react with the iron,so as to vulcanize the inside of the pipe wall and make the oxide film loose,split or even fall off at the same time.The finned tube perforation is due to the synergistic effect of thermal fatigue and high temperature corrosion of free sulfur.
