9th ECCC European Continuous Casting Conference – ECCC 2017

Steel meniscus fluctuations and level deformations in CC mold are one cause of the defect occurrence on slabs and later on coils. Slivers, which are one of the most costly defects observed on coils, are partly due to slag entrapment in CC mold. Actually, a strongly deformed meniscus and sudden meniscus level fluctuations favor the slag carry-away into the steel and entrapment of slag droplets in the solidifying shell in mold. Process parameters (such as mold width, casting speed, argon flow rate …) or events (such as clogging, breakout alarms …) impact directly steel flows in mold through the meniscus velocity and the flow pattern but through the meniscus deformation and steel level fluctuations as well. Following these last data would enable to better understand what happens in the mold and to act efficiently to improve the product quality. ArcelorMittal Research and Vesuvius developed a tool to measure on-line the steel level along half of the mold width. The device is composed of a robotized manipulator arm which insures the translation/rotation movements of an Eddy-current head, similar to the one used for mold level control. The first prototype was installed on an ArcelorMittal caster. The equipment is fixed on the tundish car and can operate just after the sequence start-up. Measurement campaigns showed the impact of casting parameters on the meniscus deformation. Position of “waves” actually depends on the mold width and the casting speed. It was also noticed that the intensity of level fluctuations is not constant during casting even if the process parameters are kept constant. This equipment is therefore an interesting and relevant tool to better control the casting process and drastically reduce the mold slag carry-away at meniscus, which could be at origin of many defects such as slivers.