Sen Luo

To improve the surface quality of low‐carbon steel slabs under high casting speed conditions, this study systematically investigated the effects of casting speed and electromagnetic braking (EMBr) on the formation of hooks and the characteristics of inclusions through a combination of numerical simulations and industrial experiments. The results indicated that as the casting speed increases from 1.4 to 1.8 m/min, the temperature of the meniscus region rises, the solidification of the hook is inhibited, and the hook depth decreases significantly. Meanwhile, the high casting speed intensifies the scouring effect at the solidification front, leading to a significant reduction in the number density of inclusions near the surface. When EMBr is applied under high casting speed conditions, the Lorentz force lifts the main flow upward, enhancing heat supply to the meniscus region and further decreasing the hook depth. However, the upward deflection of the flow jet causes more inclusions to enter the upper recirculation zone, resulting in a slight increase in the overall number density of inclusions, while the number density of large‐sized inclusions continues to decrease. Overall, the synergistic effect of high casting speed and EMBr effectively reduces the hook depth and decreases the probability of large‐sized inclusion entrapment.

A mathematical model is adopted to explore the initial solidification and slag consumption behavior within the mold under both nonsinusoidal and sinusoidal oscillation modes. Differences in liquid slag infiltration, pressure distribution, heat transfer, transient slag consumption, and oscillation mark profiles are also revealed. The results show that during the positive strip time, the mold, carrying the slag rim, moves upward relative to the shell, and the widening of the channel facilitates the infiltration of liquid slag. Although the velocity profile during the negative strip time is steeper under the nonsinusoidal oscillation, the shorter duration of this phase leads to weaker pressure fluctuations and a reduced impact on the meniscus profile compared to the sinusoidal oscillation mode. Owing to the weaker influence of the nonsinusoidal oscillation on the meniscus profile, the average depth of oscillation marks decreases from 0.30 mm under the sinusoidal mode to 0.26 mm under the nonsinusoidal mode. Meanwhile, compared to the sinusoidal oscillation mode, although the oscillation mark slag consumption decreases under the nonsinusoidal oscillation mode, the lubrication slag consumption increases. As a result, the total slag consumption under the nonsinusoidal oscillation mode increased from 5.24 g (m s) ⁻¹ under the sinusoidal oscillation mode to 6.43 g (m s) ⁻¹ .