| 摘要 |
PROBLEM TO BE SOLVED: To refine molten steel with high efficiency by estimating a circulating flow rate of the molten steel in an RH vacuum degassing apparatus, and simultaneously adjusting the circulating flow rate of the molten steel into the maximum value. SOLUTION: The RH vacuum degassing apparatus 1 has a dip tube 8 which has a plurality of nozzles 10 therein for blowing the circulation flow gas, and circulates the molten steel 3 by blowing the circulation flow gas therethrough. The estimating method includes calculating the circulating flow rate of the molten steel in the above degassing apparatus by using a flow rate of the circulation flow gas, the number of arranged nozzles for blowing the circulation flow gas, the inner diameter of the nozzle for blowing the circulation flow gas, and the following expression (1): W∝N<SP>-0.0238</SP>d<SB>b</SB><SP>-1.357</SP>Qg<SP>0.881</SP>, wherein (W) represents the circulating flow rate of the molten steel (kg/sec); (N) represents the number of arranged nozzles for blowing the circulation flow gas; (d<SB>b</SB>) represents the diameter of a bubble in the circulation flow gas (m); and (Q<SB>g</SB>) represents the flow rate of the circulation flow gas (m<SP>3</SP>/sec). The blowing method includes adjusting one or more factors selected from the flow rate of the circulation flow gas, the number of arranged nozzles for blowing the circulation flow gas, and the inner diameter of the nozzle for blowing the circulation gas, so that the calculated circulating flow rate of the molten steel can be a targeted flow rate. COPYRIGHT: (C)2008,JPO&INPIT
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