Development and Application of On-Line Solution Annealing Process for 304 Austenitic Stainless Steel

After hot rolling, 304 austenitic stainless steel requires a solution annealing treatment to prevent intergranular corrosion and eliminate work hardening effects. Compared to traditional offline processes, on-line solution annealing offers advantages in terms of cost and time savings. However, both recrystallization behavior and M₂₃C₆ carbide precipitation behavior are significantly influenced by the cooling process after rolling, which poses conflicting requirements. This study investigates the precipitation behavior of M₂₃C₆ carbides and the recrystallization softening behavior during the continuous cooling process of hot-rolled samples. The kinetics equations are derived using the Scheil's additivity rule. The temperature profiles in different regions of the plate are studied using finite element analysis. A practical approach for online solution annealing is proposed and applied in industrial testing.