| 摘要 |
PURPOSE:To prevent the longitudinal cracking of a broad steel ingot near the centralds part of the broad side in the stage of casting continuously said ingot by applying driving force to the unsolidified melt around an immersion nozzle right under the molten metal surface in a casting mold thereby fluidizing the unsolidified melt between the immersion nozzle and the long side of the casting mold. CONSTITUTION:Gas passages 32, 33 are formed separately from a molten steel downflow path 31 in the immersion nozzle 3 and porous plugs 61, 62 communicating with the passages 32, 33 are provided to the bottom end of the nozzle 3. A gas 7 which is an insert gas such as gaseous Ar and does not affect adversely a molten steel (unsolidified melt) 1 is then blown through the passages 32, 33 and the plugs 61, 62 into the molten steel 1. The driving force is thus applied to the molten steel 1 around the nozzle 3 by the gas 7 and the molten steel 1 in the regions A1, A2 between the nozzle 3 and the long sides 2C, 2D of the casting mold is fluidized. |
