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

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 U-shaped 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.