Optimization of Galvannealing Parameters through Numerical Modeling of Galvannealing Process

In the galvannealing process, a galvanized sheet is subjected to an annealing treatment to transform the zinc-coated steel sheet to iron-zinc alloy-coated steel. In the present work, the galvannealing process has been treated as a binary multiphase diffusional phase transformation reaction, and a rigorous mathematical model has been developed to simulate the galvannealing process. The results obtained by the model have been compared with experimental as well as plant data, and the results have been found to be in good agreement. The model prediction shows that the excessive growth of undesirable Γ and Γ₁ phases takes place when the iron content in the coating exceeds around 11 pct during galvannealing. It has also been observed that decreasing the line speed to obtain the desired iron content in the coating leads to excessive growth of the undesirable Γ and Γ₁ phases. It has been concluded that the developed mathematical model can be used to optimize the galvannealing parameters.