| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a refining method in a converter excellent in suppression effect of dust generation. <P>SOLUTION: In the refining method in a converter by using molten pig iron having a silicon concentration of≥0.15 mass% and not subjected to molten pig iron pretreatment, oxygen blowing refining from a lance is adjusted by using a lance blowing refining index corresponding to the shape of cavity at each stage of the blowing. As the lance blowing refining index, either the surface area of the cavity or a ratio between a cavity diameter and a cavity depth is used. At the initial stage and the end stage of the blowing, the surface area of the cavity is used, whereas at the medium term of the blowing, the ratio between the cavity diameter and the cavity depth is used. At the initial stage of the blowing, the oxygen injection from the lance is performed in such a way that the dimensionless surface area of the cavity becomes≤0.6, at the medium term of the blowing, the oxygen injection from the lance is performed in such a way that the ratio L/D between the diameter D of the cavity and the depth thereof L becomes≥0.85, and at the end stage of the blowing, the oxygen injection from the lance is performed in such a way that the dimensionless surface area of the cavity becomes≤0.6. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
