Decreasing the clogging deposition rate of alumina inclusions in continuous casting nozzles is possible through three simultaneous measures: Flow modification, use of raw materials with low impurities contents, and smoothed internal surfaces. The control of the internal flow consists on avoiding dead regions and developing symmetric patterns. A mathematical model performed tests of the feasibility of these measures. The adherence of inclusions to the nozzle wall, using this model, employs a boundary condition based on the thickness of the sublaminar boundary instead of the conventional “trap” boundary condition. The use of the general boundary condition yields deposition rates that are unaffected by the inclusion size. The proposed boundary condition discriminates against the clogging deposition rate through the particle sizes. Plant trials complemented with water modeling, using these nozzles, proved that the present approach could considerably decrease the clogging occurrence.

The turbulent phenomena occurring in the thin slab mold affect the final product quality. Therefore, it is essential to carry out studies to understand and control their occurrence. Current research aims to study the electromagnetic brake (EMBr) effects on the flow patterns in a funnel thin slab mold. The objective is to prevent the detrimental phenomenon known as dynamic distortions (DD) of the flow, applying the EMBr in the typical horizontal position (H-EMBr) and a new vertical position close to the narrow faces (V-EMBr). The fluid dynamics are simulated using the Reynolds stress model (RSM), the Volume of Fluid (VOF) model and the Maxwell equations in their magnetohydrodynamics (MHD) simplification. The results show that the H-EMBr effectively counteracts the DD phenomenon by reducing the submerged entry nozzle (SEN) ports' mass flow rate differences. The EMBr reduces the highest meniscus fluctuations from −10 to ±3 mm with a field intensity of 0.1T and almost 0 mm for higher field intensities. In contrast, the V-EMBr configuration does not reduce or control at all the DD phenomenon, even though eliminating the upper roll flows does not diminish the meniscus fluctuation amplitudes and induces new small roll flows close to the SEN's wall.

The main function of the tundish is to constantly provide molten steel to each strand, for which it is important to determine the uniformity of residence times, particularly in multiple-strand tundishes. In this study, the residence time distribution, minimum and maximum concentrations, and active and dead volume fractions were determined in a 5-strands asymmetric tundish equipped with turbulence inhibitors and argon curtains. Physical modelling was used as a tool, for which a 1:3 reduced-scale analogous water model of the prototype tundish was designed and constructed. For the experimental analysis four cases were studied, the stimulus-response technique was used, in which an inert tracer (HCl) was injected as a pulse at the ladle shroud, the change in the water conductivity was measured at each of the strands, the minimum residence times and the times at which the concentration was maximum were measured and recorded, and the residence time distribution (RTD) curves were plotted; a mixed model was used to characterize the active flow volume fractions (piston and mixed) and dead volume fraction. From the analysis and discussion of the results, no uniformity was observed in any of the four cases studied for the maximum concentration time. The hexagonal turbulence inhibitor alone achieved a result very similar to that of the arrangements with argon diffuser in their characteristics and flow distribution. The use of argon diffusers is recommended to improve the cleanliness of steel.