Corrosion Reason of Pipeline of a Medium-temperature Superheater

A medium-temperature superheater pipeline leaked after about 9 500 hours of operation. The corrosion causes of pipe fittings were analyzed by chemical composition analysis, microstructure observation, phase analysis of corrosion products and other methods. The results showed that when the pipeline was used in high temperature and strong corrosive environment, Cl element destroyed the dense oxide film, corroded the metal matrix, and generated loose low melting point compounds. Under the scouring action of high-temperature flue gas, the outer wall of the pipe gradually thined until the perforation and leakage occurred.