| 摘要 |
PURPOSE:To lower the linear velocity of molten metal and obtain an ingot of high quality free from defects by providing the 2nd tundish of sealed construction, and evacuating the inside thereof through vacuum suction. CONSTITUTION:Molten steel 5 is supplied at a constant rate into respective tundishes 1, 7a, 7b and molds 14a, 14b, and the inside of the 2nd tundishes 7a, 7b is evacuated by vacuum suction with a vacuum pump 13 and a vacuum tank 12, and in the state of closing gates 8a, 8b, the static iron columns in the tundishes 7a, 7b on the basis of the melt levels in the molds 14a, 14b are set equal to atmospheric pressure. The respective gate mechanisms 8a, 8b are operated to open communication holes 6a, 6b, and ingots Sa, Sb are drawn continuously at prescribed speeds from the molds 14a, 14b. The rates of lubrication to the molds 14a, 14b are controlled with the mechanisms 8a, 8b. Since the flow passage areas of immersion nozzles 15a, 15b are considerably larger than the opening areas of the mechanisms 8a, 8b, the linear velocity of the molten steel 5 flowing down in the nozzles 15a, 15b decreases considerably. |
