Flow field, heat transfer and inclusion behavior in a round bloom mold under effect of a swirling flow submerged entry nozzle

Flow field, heat transfer and inclusion behavior in a 700 mm round bloom mold under the effect of a swirling flow submerged entry nozzle (SEN) were investigated with the aim to enhance the casting process. The results indicate that the impinging flow phenomenon, which is commonly observed in conventional single-port SEN casting, was completely suppressed by the swirling flow SEN coming from a novel swirling flow generator design in tundish. Steel from the SEN port moved towards the mold wall in 360° direction, leading to a uniform temperature distribution in the mold. Compared to a conventional single-port SEN casting, the steel super-heat was decreased by about 5 K at the mold center, and the temperature was increased by around 3.5 K near the meniscus. In addition, the removal ratio of inclusions to the mold top surface in the swirling flow SEN casting was found to be increased. Specifically, the removal ratio of spherical inclusions with diameters of 1, 10, 50 and 100 μm was increased by 18.2%, 18.5%, 22.6% and 42.7%, respectively. Furthermore, the ratio was raised by 18.2%, 20.8%, 21.5% and 44.1% for non-spherical inclusions, respectively.