Causes of superheater pipe cracking

A secondary superheater cracked after 2 months of use. The causes of pipeline burst were analyzed by means of macroscopic observation, chemical composition analysis, X-ray diffraction analysis, scanning electron microscopy and energy spectrum analysis, metallographic examination and so on. The results show that the high temperature flue gas outside the pipeline contained sulfur, phosphorus, chlorine and other elements, among which the content of sulfur was high, which led to the oxidative corrosion of the outer wall of the pipeline. The corrosion thinning of the pipeline under the action of flue gas erosion led to the decrease of its bearing capacity. Finally, the one-time burst occured in the area with serious thinning of the pipeline under the action of internal steam pressure.