Numerical Simulation of the Fluid Flow, Heat Transfer, and Solidification in Ultrahigh Speed Continuous Casting Billet Mold

Ultrahigh-speed casting is the most remarkable feature of billet high-efficiency continuous casting. The transient fluid flow, heat transfer, and solidification behavior under different casting speeds, submerged entry nozzle (SEN) parameters, and mold electromagnetic stirring (M-EMS) are investigated using a 3D transient mathematical model. The results show that a typical roll flow pattern is generated for all casting speeds, while a third small recirculation zone developed near the solidified shell at the casting speed of 6.0 m min⁻¹. When the casting speed increases, the impact depth of the molten steel increases from 0.748 to 0.844 m, the velocity and level fluctuation at the steel/slag interface increases, the high-temperature zone moves downward, and the shell thickness is reduced from 16.2 to 11.1 mm. As the SEN inner diameter and immersion depth increases, the impact depth increases, the velocity and level fluctuation at the steel/slag interface decreases, and the shell thickness at the mold exit is ≈11.0 mm. When the SEN immersion depth and inner diameter are 120 and 40 mm, respectively, the flow and temperature fields in the mold are the most appropriate. In addition, the M-EMS have a great effect on the fluid flow and heat transfer behavior.