Selective oxidation of dual phase steel after annealing at different dew points

► Selective oxidation of a dual phase steel after annealing at different dew points. ► External selective oxidation of phosphorus occurred on steel surface annealed at 0 °C dp. ► External selective oxidation of Mn, Si, and Al occurred on steel annealed at −60 °C dp. ► Mo content increased as the depth from the surface of steels increased.