No abstract

A multi-mode electromagnetic stirring technology (MM-EMS) delivered by Danieli-Rotelec Company has been implemented in ArcelorMittal Gent CC2. This solution is able to control the liquid steel flows in CC mould by braking, accelerating or stirring them through the use of three different modes: EMLS, EMLA and EMRS. This paper presents the methodology followed in order to optimize the working of this new technology for improving the quality of products in terms of slivers defects. Different tools were developed and used by ArcelorMittal Maizières R&D to reach this objective: Numerical simulation with MagnetoHydroDynamics (MHD) tool to simulate the fluid flows in mould under the influence of magnetic fields, Submeniscus Velocity Control (SVC) tool to directly measure the liquid steel flows in the mould and finally some quality investigation tool like Automatic Surface Inspection System to detect defects directly on coils and qualify quality of products. Numerical and experimental approaches were associated to finally deliver to ArcelorMittal Gent steelplant an optimized actuator efficient for reducing defects in slabs and improving the final quality of products.

-The submeniscus velocity has a big influence on the surface quality of slabs. Slabs casted with a low casting speed result in a low submeniscus velocity and suffer more from Al-inclusions, while slabs casted with a higher casting speed have a higher submeniscus velocity and suffer more from mould powder inclusions. If the submeniscus velocity can be controlled, the amount of slivers has to be reduced. ArcelorMittal Ghent decided to install an ElectroMagnetic Actuator (EMA) to control this submeniscus velocity. This topic shows what the impact of the EMA can be on slivers.