Advantageof anticlogging nozzles over conventional aluminographite nozzles in continuous casting of steel slabs

Abstract

The goal of this work was to establish the advantages of the application of anticlogging nozzles compared with conventional aluminographite nozzles in the continuous casting of steel slabs. Anticlogging nozzles are used in many steelmaking plants to inhibit scab formation at the internal side of the nozzle wall. The formation of aluminate-corundum scab decreases internal nozzle diameter, leading to the reduction of steel flow and eventual blocking of the nozzle. The results of monitoring the behaviour of a large number of conventional aluminographite and anticlogging nozzles in a campaign lasting two months are presented. The data reveal lower average values of internal erosion caused by the steel and reduced thicknesses of scab formed at the internal side of the anticlogging nozzle wall relative to conventional nozzles. At the same time, the average values of external erosion, caused by the action of ungranulated casting powders, were considerably increased relative to external erosion resulting from the action of granulated casting powder.