Anti-fouling of submerged entry nozzle with electric current pulse

An effective method for anti-clogging of submerged entry nozzle (SEN) was developed by imposing an electric current pulse (ECP) between the SEN and the stopper in the continuous casting process. The morphologies and components of the adhered inclusions on the inner wall of SEN were examined. The size distribution and amounts of inclusions in the steel slab were measured and compared before and after treatment with ECP. After ECP treatment, the tap hole of SEN was only slightly clogged, the inner wall became smooth and the thickness of adhered inclusions decreased by about 50%. The ECP effect was also reflected in the inclusion amounts of the formed steel slab, which decreased by approximately 30% compared to the non-treated sample. These improvements were attributed to the ECP transferring excess negative charges to the molten steel side and maintaining a low or even a zero electric potential difference between the SEN and molten steel, which decreased the wettability and the interaction between the two phases.