Study on the In-mold Flow Behavior Driven by a Subsurface Electromagnetic Stirring for IF Steel Slab Casting

A three-dimensional numerical model coupling the electromagnetic field, fluid flow, and level fluctuation has been developed to investigate the flow behavior of molten steel in a slab continuous casting mold for interstitial-free (IF) steel. According to the industrial and modeling results, the swirls are generated on the cross-section due to the electromagnetic force (EMF) and its number relies on the magnetic pole pairs of electromagnetic fields. With the increase in current frequency, the EMF reaches the maximum at the current frequency of 4.5 Hz and then gradually decreases. When the current intensity increases from 0 to 600 A, the rate of slag entrapment related to the billet defects is decreased from 7.46 to 1.09%, but it increases to 6.09% when the current intensity reaches 650 A. The study suggests that the optimized current intensity of mold-electromagnetic stirring (M-EMS) can effectively prevent surface or subsurface defects for clean steel production.