| 摘要 |
PURPOSE:To decrease the unit of inert gases without decrease in a degassing effect in a degassing treatment for molten metal by changing the rate of blowing of the inert gases in accordance with the gaseous components in the molten metal changing during degassing reaction. CONSTITUTION:Molten metal is put in a refining vessel, and an inert gas such as gaseous Ar is blown through a porous plug or tuyere therein to degass the molten metal. The rate of blowing of the inert gas is changed in this stage in accordance with the level of the gaseous components in the molten metal. In dehydrogenation, for example, the flow rate of Ar is set slightly low and dehydrogenetion is progressed efficiently at the suppressed flow rate of the Ar, then the flow rate of Ar is increared as the conc. of hydrogen decreases, in the region where the initial concn. of hydrogen in the molten metal is high. The flow rate of the Ar is increased to decrease the ultimate level of concn. of hydrogen, in the region whee the concn. of hydrogen is low. The optimum flow rate for blowing of the inert gas is similarly determined according to the levels of N, O in the case of degassing of N2 and O2. |
