Numerical study on the effects of strands consistency on metallurgical transport behaviours of low-carbon steel in tundish–submerged entry nozzle–mould systems

In this study, the innovative tundish–submerged entry nozzle (SEN)–mould systems that enabled data transmission between the tundish and the mould were constructed to investigate the effect of strands consistency on the metallurgical transport behaviours of low-carbon steel. The velocity magnitude near stopper-rod A and T-outlet A was notably low. Owing to inactive flow regions and temperature variations near the stopper-rods, the maximum temperature difference between T-outlet A and T-outlet B was approximately 2.8 K. In case 2, a vortex occurred near the right narrow face of the steel–slag interface, while no vortex was present near the left narrow face. In cases 3, 5 and 6, some streamlines existed approximately perpendicular to the steel–slag interface. These phenomena increased the possibility of slag entrainment via the upward flow mechanism and shear layer instability. Cases belonging to strand A featured a higher temperature gradient than cases belonging to strand B, and this trend was related to the temperature difference between T-outlet A and T-outlet B. The extreme differences in temperature gradient were 0.067 K/mm for case 3 and 0.056 K/mm for case 4. At an SEN port angle of 15°, strands consistency had the greatest influence on the uniformity of the temperature gradient. Different solutes exhibited similar distribution patterns, and solute segregation was closely related to the partition coefficient. Various velocity components and SEN structures determined the position of the impact point, thereby influencing fluid flow and temperature distribution in the mould. The concentration distribution of solutes was closely related to the velocity at T-outlet A/B. The thickness of the solidified shell and mushy zone closely depended on the temperature at T-outlet A/B. Strands consistency impacted metallurgical transport behaviours in the mould and the quality of the bloom.