Effect of phase transformation latent heat on prediction accuracy of strip laminar cooling

Abstract

The cooling of hot-rolled strips is of great importance due to its effects on the mechanical and metallurgical properties of the final product. In this paper, the effect of phase transformation on accurate prediction of strip temperature at the run-out table is investigated. For this purpose, a model is developed for the heat transfer and phase transformation in hot-rolled strips during the cooling process. The model is capable of calculating strip temperature and the volume fraction of steel phases during cooling at the run-out table under the two different situations of “regarding phase transformation latent heat” (RPTLH) and “disregarding phase transformation latent heat” (DPTLH). Actual data from a hot rolling line were used to evaluate the accuracy of the model. The model was used to predict strip temperature under the above two scenarios. Comparison of actual and predicted values in the two DPTLH and RPTLH cases revealed that disregarding the released heat would lead to considerable errors in temperature predictions. The results for different steel grades predicted by the model also showed that the higher the carbon content of the steel, the higher the error due to disregarding phase transformation latent heat.