Effect of Submerged Entry Nozzle Structure on Fluid Flow, Slag Entrainment, and Solidification Process in a Slab Continuous Casting Mold

The fluid flow and slag entrainment in a slab continuous casting mold were investigated by establishing a full-scale water model. Meanwhile, the heat transfer and solidification process of liquid steel in the mold were studied through numerical simulation. The effect of two different submerged entry nozzles (SENs) was compared and analyzed, named as original SEN and L1 SEN, respectively. The results indicate that the structure of the SEN has a significant influence on the fluid flow pattern and solidification process in the slab mold. For the original SEN, the liquid level in the mold fluctuated obviously and the slag phase was easily entrained into the mold. The percentage of ±3mm level fluctuation was 57.2-74.3%. By enlarging the exit size, the L1 SEN considerably reduced the jet velocity at the nozzle exit and subsequently decreased the surface velocity at the top surface. The level fluctuation and slag entrainment in the mold have been effectively controlled. The percentage of ±3mm level fluctuation was increased to 91.7-98.6%. Furthermore, under the condition of L1 SEN, the thickness of the solidifying shell at the mold outlet was increased from 13.5 mm to 16.4 mm, which was beneficial to decrease the risk of breakouts and quality problems.