Influence of Cr and Ni content in stainless steel on the degradation mechanisms in PbO–CaO–SiO2 slag

Degradation of stainless steel in contact with PbO–CaO–SiO2 slag at 1200 °C is experimentally investigated. The contact between steel and slag leads to the reduction of PbO from the slag to liquid Pb, and concurrent oxidation of the steel. The degradation mechanisms can be divided into liquid slag and liquid metal corrosion and oxidation. High Cr content is beneficial as it promotes the formation of a Cr2O3 scale which shields the steel from the slag and liquid Pb. The high solubility of Ni in liquid Pb is responsible for the increasing dissolution rate with increasing Ni content of the steel.

► Degradation of stainless steel in contact with PbO–CaO–SiO2 slag at 1200 °C.
► Experimental study supported with thermodynamic calculations.
► Degradation mechanisms are liquid slag and liquid metal corrosion and oxidation.
► High Cr content is necessary but not sufficient to form protective Cr2O3 scale.
► Degradation increases with Ni content due to high solubility of Ni in liquid Pb.