| 摘要 |
PURPOSE:To produce ultra-low phosphorus steel in a converter by contg. powder of slag forming agents such as quicklime into the gaseous oxygen flow to be top blown, blowing the same thoroughly deeply into the molten iron, blowing an inert gas or the like under the bath surface and mixing the bath uniformly for a prescribed time. CONSTITUTION:Powder mixed with >=1 kind slag forming agents such as quicklime, limestone, fluorite, dolomite or the like is mixed in the gaseous oxygen flow to be top blown by a lance B having a nozzle head part A, and is blown into the bath under the condition under which the above-mentioned powder is intruded in the bath at >=30% of the bath depth, in a steel making method by top blowing of oxygen in a converter CV>=1 kinds among inert gas, gaseous nitrogen, gaseous oxygen gaseous carbon monoxide and gaseous carbon dioxide are blown through a tuyere N into the molten metal below the bath surface S under the condition under which the bath is mixed uniformly for 30-100sec during the period of blowing operation by oxygen top blowing or until the discharging period after the end of the blowing in succession to said period, whereby the slag having >=5 basicity is formed and the ultra-low phosphorus steel is produced. |
