The influence of high-temperature oxidation on the phase distribution of metal substrate in duplex stainless steel

Abstract Duplex stainless steels (DSSs), which consist of ferrite and austenite phases, are widely used owing to their high strength good corrosion resistance. However, the oxidation behavior DSSs is extremely complicated because they have dual phases. In this study, changes in scale metal substrate during were investigated. UNS S32101 (Fe-21.5%Cr–5%Mn–1.5%Ni–0.3%Mo–0.22%N), a typical type DSS, was annealed at 1473 K for up 36 ks air. The microstructure consisted austenite/ferrite ratio 50:50 room temperature. After oxidation, Cr, Mn-oxide formed predominantly. beneath changed mostly ferrite. same region, depletion Mn N concentrations resulted. decrease due formation Mn-oxide. addition, it revealed that content decreased 2 gas along with Mn. It assumed N, austenite-stabilized elements, led an increase area N. From result, expected compositional Mn/N caused by steel.