Failure Analysis on Corrosion and Perforation of High Chromium White Cast Iron Grate Plate in a Waste Incinerator

After a certain waste incinerator was put into operation for 17 440 h, corrosion and perforation failure happened to its high chromium white cast iron grate plate. Through the methods of macroscopic inspection, chemical composition analysis, metallographic examination, hardness test, scanning electron microscopy and energy spectrum analysis, the corrosion and perforation reasons of the grate plate were analyzed. The results show that the cooling air flow was insufficient during the operation of the unit, and corrosive elements such as chlorine and sulfur in the garbage led to the high-temperature corrosion reaction of the grate plate at the segregation position of chromium. The corrosion products continuously fell off under the rapid flushing of high-temperature flue gas, which made the wall thickness of the grate plate thinning. Finally, corrosion and perforation failure occurred at the weak position.