Theoretical and experimental analysis of selective oxide and nitride formation in Fe–Al alloys

• Internal oxide and nitride formation in Fe–Al alloys is studied.
• Steel slab reheating conditions.
• Corrosion depth and formed phases determined using SEM/EDX and XRD.
• Numerical simulation of the phase distribution is calculated.
• Sub-surface oxide bands were found in several samples.

Selective oxidation experiments of four iron-aluminum model alloys, containing 1–8 wt.% Al, at temperatures up to 1285 °C have been performed. The total corrosion depth and composition of formed nitride and oxide phases have been analyzed by means of SEM/EDX and XRD. Experimental findings and the interplay between formed oxide and nitride phases were compared to theoretical predictions from numerical simulations and critically discussed.Conditions for the formation of a continuous oxide band underneath the sample surface will be highlighted, which represent a critical parameter window in industrial processes that may lead to severe mechanical damage during rolling.