2019 年 59 巻 1 号 p. 86-92
The melt flow and bubble motion in a 230×1300 mm2 continuous casting slab mold were investigated under different inclination angle, divergent angles and immersion depth of the submerged entry nozzle (SEN) and different argon gas injection rates using a volume of fluid (VOF) and discrete phase model (DPM) to avoid slag entrapment and enhance the removal rate of nonmetallic inclusions. Water-model experiments were conducted to validate the numerical models. Moreover, the optimized conditions were applied in a manufacturing plant. The results showed that the simulated steel/slag level fluctuation and argon bubble trajectories are consistent with the experimental results. The optimized SEN structure has an inclination angle of 20° and a divergent angle of 9°, which can improve the flow pattern in the steel/slag interface, alleviate the level fluctuations, decrease the chance of slag entrapment, and optimize the movement of inclusions. The immersion depth of SEN should be 150 mm, which is beneficial to the floating removal of non-metallic inclusions and reduce the level fluctuation at steel/slag interface. The optimal argon gas blowing rate to avoid slag entrapment near the SEN is 10 L/min. Furthermore, the rate of edge defects (ED) in the hot roll strip induced by slag entrapment is apparently reduced by applying the above conditions.
