STEELMAKING METHOD IN CONVERTER

摘要

PURPOSE:To reduce the fixed cost and the variable cost of dephosphorizing treatment and to eliminate the development of dust by repeating an operation of deoxidation by adding carbonaceous material into slag after executing the dephosphorization, slag-off, decarbonization and steel-tapping and an operation of charging the following heat for molten iron, in a converter. CONSTITUTION:Into the top-bottom combined blowing converter, iron scrap and the molten iron are charged and by adding flux for dephosphorizing, oxygen is blown to execute the dephosphorizing treatment in the high carbon and low temp. range of the molten iron. By tilting the furnace, the slag is flowed out, and also, by increasing gas flow rate in a tuyere at the furnace bottom side, the molten iron at the furnace bottom side is made to the boiling condition and the remained slag in the furnace is flowed out from the furnace opening part. After removing the slag, the furnace is elected to the normal position and by charging auxiliary material, the decarbonizing refining is executed by top and bottom blowing. After stopping the blowing, the steel tapping is executed, but the slag is remained in the furnace and utilized as slag-making agent for dephosphorizing in the following heat. The furnace posture is made to the normal posture and the carbonaceous material is charged and the slag is beforehand deoxidized so as to become <= about 5% FeO concn. by the gas stirring from the furnace bottom. Thereafter, the following heat of molten iron is charged into the furnace and the same operation is repeated.