Optimum Magnetic Flux Density in Quality Control of Casts with Level DC Magnetic Field in Continuous Casting Mold

Abstract

Application of level DC magnetic field (LMF) in continuous casting mold decreases the mixing length at the ladle change region in sequential casting of different steel grades and improves the inclusion quality of cast slabs. Until now control condition for the mixing of steel compositions which depends on the fluid flow of molten steel has only been clarified. However, control condition for the inclusion whose behavior is not always the same as the behavior of the molten steel flow has not been clarified yet. In this study, continuous casting experiment and numerical analysis were conducted to derive the control index for inclusion and to estimate the optimum condition for improvement of inclusion quality in cast slabs with LMF. The followings are results: Optimum magnetic flux density exists to control the inclusion quality in cast slabs with LMF. Inclusion behavior is explained by the balance between the penetration of inclusion controlled by magnetic field and the floatation of inclusion. This optimum magnetic flux density can be characterized by the interaction parameter, which is expressed by the ratio of inertial force caused by pouring flow to magnetic braking force (Lorentz's force) caused by magnetic field.