1998 Volume 47 Issue 12 Pages 777-782
High temperature corrosion behavior of a SCH 13 steel in a waste incineration furnace, where used plastics and tires were burned in the day-after-day operation, was investigated by means of optical microscope and scanning electron microscope, electron probe micro-analysis, and X-ray diffraction analysis. The SCH 13 steel was put at the exit of the furnace, and the temperature of exhaust gases maintained above 1273K (maximum is 1423K) for 7ks and then at 1150K for 17ks, followed by furnace cooling. Corrosion products in the surface were mainly oxides as Cr2O3, Fe3O4, NiMn2O4, and FeCr2O4. Internal corrosion products with a network structure were composed of Cr-Mn oxide, and at the internal corrosion front SiO2 and CrS were formed in link with Cr-Fe carbides and σ-phase, which were precipitated in a network structure during the repeated furnace operation. Laboratory tests on sulfidation or oxidation of both as-received and heat-treated SCH 13 steels showed that the Cr-Fe carbides and σ-phase were preferentially corroded, forming a network structure. It could be concluded that the internal corrosion of the SCH 13 steel suffered from the waste incinerator atmosphere is due to selective sulfidation of Cr-Fe carbides and σ-phase in the internal corrosion front, followed by oxidation to form SiO2 and Cr-Mn oxide.