| 摘要 |
PURPOSE:To economically produce good killed steel free from any surface defect by tapping under the undeoxidized state, the molten steel having been melted in an oxygen bottom blowing converter, and reducing the hydrogen content through boiling at the tapping then adding an Al-base deoxidizer. CONSTITUTION:The molten steel having been melted in an oxygen bottom blowing converter has a high hydrogen content because a hydrocarbon cooling agent is used for preventing the erosion of furnace bottom nozzles. Thereupon, this molten steel is tapped in an undeoxidized state, and part of the hydrogen in the molten steel is allowed to dissipate into the atmosphere by the vigorous boiling owing to the inclusion of air etc. by the tapping flow, whereby the hydrogen content is decreased to about <=6ppm. Thence, a deoxidizer comprising Al or Al alloy is added to produce an Al killed steel or Al-Si killed steel. This method does not use any Ar gas etc. for dehydrogenation treatment and since the amount of Al to be used can be made less, this method is economical. |
