Investigation on Solid State Phase Transformations in a 2510 Duplex Stainless Steel Grade

Duplex and Super Duplex Stainless Steels are very prone to secondary phases formation related to ferrite decomposition at high temperatures. In the present paper the results on secondary phase precipitation in a 2510 Duplex Stainless Steel, heat treated in the temperature range 850-1050 °C for 3-30 minutes are presented. The precipitation starts at grain boundaries with a consistent ferrite transformation for very short times. The noses of the TTP curves are at 1000 °C for σ-phase and at 900 °C for χ-phase, respectively. The precipitation sequence involves a partial transformation of χ into σ, as previously evidenced in 2205 and 2507 grades. Furthermore, the experimental data were compared to the results of Thermo-Calc calculations.