Causes of boiler water wall tube corrosion burst

The causes of water wall tube burst of a boiler were analyzed by means of macroscopic observation, mechanical property test, metallographic examination, scanning electron microscope and energy spectrum analysis. The results show that there was corrosion thinning near the explosion port, a large amount of scaling on the fire surface of the pipe wall, a groove-type corrosion pit at the bottom of the scale layer, severe decarburization accompanied by cracks in metal matrix. Combined with the actual operation conditions, it was considered that the main reason for the tube explosion was the leakage of the condenser, which caused the unqualified circulating water to enter the boiler water. At the same time, the improper dosing method and the unreasonable regular sewage discharge caused serious under-deposit alkaline corrosion on the inner surface of the water wall to the fire surface. Finally, a series of improvement measures were proposed to avoid the recurrence of such accidents.