Five stainless steel grades are subjected to PbO-CaO-SiO2-S slag at 1200 degrees C. The degradation phenomena are identified as liquid slag and liquid metal corrosion, oxidation and sulphidation. The relation between sulphidation and steel and slag composition is discussed. For the slag with the lowest PbO/SiO2 ratio, sulphidation is mainly recognized through (Fe, Cr)(x)S1-x at the surface and in the subsurface of the steel, especially for the steel grades with the lowest Cr content. For the slag with the highest PbO/SiO2 ratio, sulphidation is mostly pronounced in the steel grades with the highest Ni content through the formation of a liquid (Ni, Pb, S) phase. (C) 2011 Elsevier Ltd. All rights reserved.