| 摘要 |
<p>PURPOSE:To control freely temp. rise of a molten iron and to improve refining efficiency in the stage of subjecting a molten iron which is preliminarily desiliconized, desulfurized and dephosphorized to slagless decarburization refining in a oxygen top blown converter and producing a molten steel by controlling adequately the depth of the depression on the surface of the molten metal formed by top blowing oxygen. CONSTITUTION:A molten iron 5 which is prelimarily desiliconized, desulfurized and dephosphorized is charged into an oxygen top blown converter 1 provided with stirring tuyeres 4 for a molten metal 5 according to need and oxygen is blown to the molten iron surface through a porous wide angle top blowing lance 3 to oxidize and decarburize the carbon contained therein to a target content to form a molten steel by slagless refining. The pressure of the oxygen blown from the lance 3 is regulated in this case to control the depth of the depression 6 formed on the surface of the molten metal 5 to a 80-400mm. range. The secondary combustion rate at which the C contained in the molten iron is once oxidized to CO and is further oxidized to CO2 is increased by which the temp. elevating rate for decarburization is improved to about 190 deg.C/1%C. The amt. of the inexpensive cold scrap is increased with the improved thermal efficiency of the converter and the cost of steel making is reduced.</p> |
