METHOD FOR RAISING TEMPERATURE OF MOLTEN STEEL IN LADLE WITH OXYGEN BLOWING

摘要

PURPOSE:To prevent erosion of refractory and clogging of a nozzle for casting caused by produced slag from the refractory material by beforehand adjusting Si content in molten steel to high and adding the specific small quantity of Al at the time of raising temp. of molten Si killed steel with oxygen blowing. CONSTITUTION:At the time of continuously cast after charging the Si killed steel 1 already refined with a ladle 2, the temp. of molten steel is raised to the temp. being suitable to casting. For this purpose, inert gas is blown from a bubbling lance 6 and after removing the molten slag 7 floated with rising bubble, a submerged tube 4 is lowered to the position having no molten slag 7 and the tip part is submerged into the molten slag 7. Fe-Si is charged from a charging tube 5 in the submerged tube 4 to adjust Si content in the molten steel 1 at higher than the aimed value. Successively, O2 gas is supplied onto the molten steel surface from a lance 3 and during this period, Al is added into the molten steel 1 at 10-5O% of the theoretical oxidation with supplied oxygen quantity. The temp. of molten Si killed steel 1 is raised with oxidation of Al and Si and also the molten slag composed of 3Al2O3.2SiO2 is generated, and the erosion of the lining refractory of submerged tube 4 and the clogging of nozzle for continuous casting can be prevented.