| 摘要 |
<p>PURPOSE:To produce excellent molten steel for continuously cast slab scarcely containing harmful inclusion by tapping the molten steel in a converter into a ladle after solidifying a large part of molten slag in the converter and blowing flux having a specific composition into a small quantity of the molten slag in the ladle. CONSTITUTION:The molten steel is tapped into the ladle after raising the m.p. of the molten slag and solidifying the molten slag by adding CaO into the molten slag existing on the molten steel refined in the converter, and the quantity the molten slag flowing out with the molten steel into the ladle together is made small as <=0.1% of the tapped molten steel quantity. FeO in the molten slag is reduced to Fe by adding Al onto a small quantity of the molten slag to make the remained FeO <=3%, and thereafter, the flux having 0-40% CaO, 60-100% Al2O3, and 50-1000mum the grain diameter is blown together with inert gas such as Ar through a lance. Then, this flux is combined with CaO-Al2O3 base inclusion in the molten steel to make the inclusion harmless to the steel, and also major part of the harmless inclusion is floated up and separated from the molten steel. The molten steel for continuously cast slab having excellent quality as the slab for steel plate without defect caused by the harmful inclusion is obtd.</p> |
