Molten steel flow control under electromagnetic level accelerator in continuous casting mold

Abstract

In a continuous casting process, magnetic coil has been applied to the molten steel flow control in a mold. Some of the magnetic coils are applied to stabilize the molten steel flow and the meniscus fluctuation to prevent powder entrapments. Others are applied to activate the molten steel flow to keep proper temperature at the meniscus or wash inclusions off near the solidification front. The Electromagnetic Level Accelerator (EMLA) has been developed to accelerate the molten steel flow from the nozzle in order to carry the molten steel to the narrow side of the mold when the casting speed is low or the mold width is wide. It applies low frequency alternating magnetic field moving from the nozzle to the narrow side of the mold just below the nozzle exits, because the electromagnetic force acts on the molten steel in the same direction as the magnetic field moving. In this study, the effect of the EMLA on the molten steel flow is investigated. Numerical simulation of the molten steel flow was carried out. The molten steel flow velocity measurement was also conducted in operation. Applying the EMLA, the molten steel flow is accelerated proportional to the imposed magnetic field. The molten steel flow from the nozzle can be controlled to reach the narrow side of the mold. Therefore, the risk of the extraordinary temperature drop at the mold corner of the meniscus decreases and the capture of the inclusions into the solidification shell that causes the surface defects is avoidable. © 2007 ISIJ.