Depression behaviour of hypo-peritectic steel in continuous casting by a mathematical model

A mathematical model to calculate the depression index with the consideration of contraction strain, strain rate and deformation resistance was newly developed, and the parameters were determined after theoretical discussion. The model was verified by various measured data. A peak point in depression index was observed in the hypo-peritectic range by the model, and the corresponding carbon content for the common high‑strength low‑alloyed steels was about 0.11% ~0.13%. The effect of alloying elements on the depression tendency was revealed. The carbon content at the peck point as functions of eight alloying elements was regressed based on 32 sets of data from mathematical model. The predicted values by the regression equation are significantly close to the original results. The steel composition can be optimised by enlarging the gap between peak point content and the actual carbon content based on the regressed equation.