Effect of asymmetric cooling on the temperature and solidification of continuous steel casting: Numerical and experimental study

Continuous casting is widely used in steelmaking industries as an efficient method to produce semi-finished products. However, this process can suffer from non-uniform solidification of the steel strand due to factors such as nozzle clogging. These phenomena can lead to defects such as local and overall distortion, cracks, and porosity, which can significantly reduce the quality of the steel product. This study employed a transient, three-dimensional numerical model to investigate the influence of asymmetric secondary cooling on the temperature distribution and solidification behaviour of steel strands during continuous casting. The model was validated using experimental data from a real steel plant. Numerical simulations were conducted to investigate the effect of various nozzle blockage scenarios, including single, dual and triple nozzle blockages. The simulations revealed that nozzle blockage leads to significant reheating of the steel strand surface in the affected area, with the local surface temperature increasing by up to 27°C, 89°C and 108°C for single, double and triple nozzle blockages, respectively, resulting in asymmetric temperature distribution and liquid fraction. The results also show that the maximum liquid fraction difference across the strand cross-section can reach about 0.091, indicating a shift of the liquid core under asymmetric cooling. This asymmetric solidification can lead to longitudinal distortion and rhomboidal deformation of the strand's cross-section. Furthermore, the study investigated the effect of casting speed on the temperature distribution during nozzle blockage. This analysis helps to improve the casting process, prevent bloom distortion and reduce production losses.