| 摘要 |
<p>PURPOSE:To obtain steel of low H2 content with high refining efficiency, by blowing prescribed quantity of O2 of all supplied oxygen into the bottom of a furnace through a bottom blowing nozzle and blowing the remaining oxygen down to the surface of molten steel through a lance pipe for all the duration of oxygen blowing. CONSTITUTION:For all the duration of blowing of oxygen into molten steel 4 in a furnace 1, gas 6 which is 2-20% by volume or less, preferably 2-13% of O2 or a mixture of O2 and neutral gas of all supplied oxygen is blown into the bottom of the molten steel through a bottom blowing double pipe nozzle consisting of an inner pipe 7 and an outer pipe 8 and the remaining oxygen is blown onto the surface of the molten steel through a top blowing lance pipe 2. The oxygen top blowing conditions are altered depending on the quantity of the gas introduced into the bottom of the molten steel. To be concrete, the more the quantity of the bottom blown gas is, the more weakly the top oxygen is blown by adjusting its quantity and the height of the lance pipe. As a result, the iron oxide content of slag 5 is controlled and strong stirring and mixing are caused by the bottom blown gas to accelerate metal slag reaction.</p> |
