Thermally grown oxide films and corrosion performance of ferritic stainless steels under simulated exhaust gas condensate conditions

•Five ferritic stainless steels with dissimilar composition included.•Thermal oxide films and performance under exhaust gas condensate conditions studied.•Oxide films grown at 300 and 600 °C show differences in structure and properties.•Performance of alloys with >11.5 wt.% Cr is related to elements Ti, Si, Nb and Mo.•Compositional optimization requires knowledge on several linked processes.

Five ferritic stainless steels are characterized in terms of thermally grown oxide films and corrosion performance under simulated exhaust gas condensate conditions. Oxide films developed at 300 °C show only little variation in microstructure and properties between the alloys, whereas those evolved at 600 °C exhibit clear differences. Especially in alloys with >11.5 wt.% chromium, the presence and distribution of such alloying elements as titanium, silicon, niobium and molybdenum are crucial for the film properties and the overall corrosion performance. The results may be exploited in the compositional optimization of the alloys for the cold-end components of automotive exhaust system.