Diffusion model for austenite formation kinetics during inter-critical annealing of dual-phase steels

A numerical solution for the ferrite-to-austenite phase transformation in a ternary iron alloy is proposed that predicts austenite formation during isothermal treatment. As the solution ensures perfect mass conservation of the solutes, it can be applied for long holding times until the system reaches final thermodynamic equilibrium. The solution was validated using previous experimental results on Fe–Ni–Cr alloys. Comparison with experimental data for a low-C, low-alloyed dual-phase steel enabled investigation of the effect of the initial concentration of the substitutional solute in cementite and the dissolution of cementite on the austenite formation kinetics.