Effect of Mold Electromagnetic Stirring on Metallurgical Behavior in Ultrahigh Speed Continuous Casting Billet Mold

Abstract

A three‐dimensional model of fluid flow, heat transfer, solidification, and inclusion motion in billet mold at ultrahigh casting speed under electromagnetic field is developed. The low Reynolds number k–ε model coupled with electromagnetic model and Lagrangian discrete phase model is used to investigate the flow field, temperature field, solidification, and inclusions transport under different current intensities. The results show that mold electromagnetic stirring (M‐EMS) significantly alters the flow pattern of molten steel. The impact depth of the molten steel decreases as the stirring current intensity increases, and the horizontal swirl intensities of the molten steel increase with the stirring current intensity. As the current intensity increases from 500 to 700 A, the impact depth decreases from 0.637 to 0.575 m and the maximum tangential velocity increases from 0.477 to 0.898 m s−1. When the stirring current is intense, the flow of molten steel near the mold exit is reversed, and the molten steel flows asymmetrically and unsteadily. The M‐EMS effectively improves the transverse heat transfer of the molten steel in the mold, contributing to the dissipation of the molten steel superheat and the growth of the solidified shell. In addition, the removal ratio of the inclusions is improved significantly.

Numerical Simulation of Fluid Flow, Solidification, and Solute Distribution in Billets under Combined Mold and Final Electromagnetic Stirring

“…(4) Low Reynolds number turbulence models are employed to simulate the flow field, in accordance with previous studies [27,28]. (5) This study does not account for the electromagnetic heat generated by EMS on the cast billet. (6) Due to the similar segregation behaviors of solute elements such as phosphorus, sulfur, and manganese in steel, this study specifically focuses on the macrosegregation behavior of carbon.…”

“…Wu et al [2] investigated the influence of M-EMS on the solidification structure of strands, and their findings indicate that increasing electromagnetic torque can refine grain size, expand the equiaxed grain zone, and improve central segregation issues. Regarding the effects of F-EMS, several production experiments have shown a significant improvement in central segregation issues [3,4], and it also offers some improvement in addressing central shrinkage concerns [5]. In addition, the experimental study by Falkus et al [6] showed that casting parameters such as casting speed also have a very obvious impact on macrosegregation.…”

Numerical Simulation of the Flow Field in an Ultrahigh-Speed Continuous Casting Billet Mold

“…Casting speed is the main factor controlling the production capacity of a continuous casting machine, but defects in billet quality that arise from higher casting speeds restrict its further improvement [25,26]. The movement toward ultrahigh-speed continuous casting is a powerful direction in the casting industry.…”