AbstractThe influence of oxidation in carbon dioxide and of heat treatment in an inert gas (argon) for up to 2000 h at 1000°C on the metallurgical structure of a 20Cr–25Ni–Nb (wt-%) stabilised stainless steel, annealed before these exposures at 930°C, has been investigated. The effect of oxidation for varying periods and of the corresponding argon heat treatments on the subsequent creep rupture properties of the steel at 750°C has also been studied. The influence of concurrent strain, from a constant applied load, on the oxidation behaviour of the same type of steel has also been examined during 100 h oxidation, in carbon dioxide at 1000°C.MST/1176