Influence of Processing on Microstructure, Mechanical Properties, and Fracture Behavior of a Cast 2507 Duplex Stainless Steel

The effect of processing on the microstructure and mechanical properties of cast duplex stainless steel 2507 is studied. It is established that the structure of hot-rolled steel contains δ-ferrite and austenite (γ) bands that change due to 50% cold rolling to form microstructural constituents of a more refined and fragmented nature of a duplex (γ +δ) phase. Austenite grains are most effectively refined (up to 5 μm) because of the recrystallization occurring during aging treatment. The cold-rolled steel has maximum strength and minimum elongation. The best combination of strength and ductility is achieved after hot deformation + solution treatment at 1040°C with water cooling and after hot deformation + solution treatment at 1300°C with water cooling followed by isothermal aging at 1000°C. Such processing ensures a good formability of the steel.