ALTERNATE STRONG AND WEAK OXYGEN BLOWING STEEL MAKING PROCESS

摘要

PURPOSE:To increase the temp. of molten iron by decarbonization and to increase the blending ratio of scrap iron in a steel making material by using molten iron which is previously desiliconized, dephosphorized, and desulfurized as an essential iron source, and repeating alternate strong and weak top blowing of oxygen against the surface of molten iron to make steel. CONSTITUTION:An agitating bottom gas blowing tuyere 4 is optionally provided to a vessel obtained by lining an iron shell 1 with a refractory material 2, and an oxygen blowing lance 3 is provided to a top-blown oxygen steel making furnace. Molten iron 5 which is previously desiliconized, dephosphorized, and desulfurized is charged into said furnace as an essential iron source, and oxygen is blown in from the top as an essential decarbonization means to make steel. The depth of a dent 6 formed on the surface of molten iron by the top blowing of oxygen is made alternately large and small, and the alternate strong and weak blowing of oxygen is continuously repeated. The secondary combustion of carbon is promoted in this way, and the temp. of molten iron is increased by decarbonization. Consequently, the blending ratio of scrap iron in the steel making material is increased, and the degree of freedom in selecting the kind of iron sources can be expanded.