| 摘要 |
PURPOSE:In converter double-slag blow-smelting of steel, particularly in the primary blow-smelting, the process is carried out by using hard blow in the former half period and soft blow in the later half blow. The soft blow is applied with additional short-time hard blow thereby assuredly providing low phosphorus steel. CONSTITUTION:For oxidation-smelting, oxygen is jetted from the lance 3 mounted above the molten steel 2 in the converter 1. In the former half period of the primary blow-smelting, a 5-minute hard blow of oxygen jet is performed so that the molten metal surface is depressed by the depth L and that the ratio L/L0 should be 0.29 to 0.32, where L0 indicates the depth of molten steel 2. Then, in the latter half period, a 5-minute soft blow is carried out so that L/L0 will be 0.10 to 0.22, with the process including one or more of short-time hard blow of about 0.3 L/L0. The process oxidizes phosphorus present in the molten steel causing phophorus to move into the slag which is exhausted. Then, a 10-minute secondary smelting process with about 0.24 L/L0 is performed to produce low-phosphorus steel. |
