| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the development of splash and to efficiently executed decarburized-refining by adding flux specifying a basicity and an Al concn. into an immersion tube to produce molten slag before starting finish decarburized-refining to molten stainless steel. SOLUTION: At the time of starting the finish decarburized-refining to the molten stainless steel and becoming about 0.3wt.% C concn. in the molten steel 11, feeding velocity of the oxidizing gas blown from a top-blown lance 18 is reduced. In this condition, the flux having 1-4 basicity (CaO/SiO2 ) in the immersion tube 13 and 5-30wt.% Al2 O3 concn., is added at 440-2650kg/unit projective area (m<2> ) of the immersion tube 13. By this method, the molten slag 16 is produced on the stainless steel 11 surface to display slag cover effect. In this result, the developing quantity of the splash and the arrival height can be restrained. Further, the finish decarburized-refining is efficiently executed by reducing the vacuum degree in the immersion tube 13 to <=200Torr.</p> |
