Degradation behavior of stainless steel in PbO-CaO-SiO2 slag in the presence of sulphur

► Degradation of stainless steel in sulphur containing lead slag at 1200 °C. ► Degradation mechanisms are studied with SEM. ► Degradation through sulphidation is related to steel and slag composition. ► Pyrrhotite forms mainly for low PbO/SiO2 ratio and for low Cr content. ► Liquid (Ni, Pb, S) phase forms for high PbO/SiO2 ratio and high Ni content.