| 摘要 |
PURPOSE:To remove efficiently the inclusions in a molten steel in the stage of transferring the molten steel in a ladle by an immersion nozzle into a tundish during continuous casting of the molten steel by adding a Ca alloy or Ca flux to the molten steel passing through the immersion nozzle. CONSTITUTION:The molten steel in the ladle 1 is transferred into the tundish 5 by the immersion nozzle constituted of an upper nozzle 2, a sliding nozzle 3 and a lower nozzle 4 to be immersed into the molten steel and is poured continuously from the bottom nozzle of the tundish 5 into the mold for continuous casting, by which a steel ingot is produced. The powder of the Ca metal such as metallic Ca powder, Ca-Si powder or the powder of the Ca flux such as CaO or Cao- CaF2 is blown together with gaseous Ar, He, CO or CO2 from the blow port provided to the upper plate of the nozzle 3 or the nozzle 4 to the molten steel flowing down in the nozzle. The Ca metal and flux adsorb the non-metallic inclusions such as Al2O3 in the molten metal by the thorough mixing and contacting with the molten steel and remove such inclusions from the molten steel. The steel ingot having the clean material quality is thus produced. |
