| 摘要 |
PURPOSE:To manufacture an immersion nozzle having a slit of a perfect shape by burying a prefired product coated with a specific slit forming material around a core bar in a refractory material for a nozzle body and firing the same, in manufacturing an immersion nozzle for casting provided with a slit. CONSTITUTION:A refractory material 2 as a nozzle material is packed up to prescribed height in a rubber mold 1 for nozzle forming, a core bar 3 which is beforehand erected at the center thereof is coated and fitted uniformly to prescribed thickness with a slit forming material 5 of less residual carbon of the case where a preforming 4' of a gas percolating body is fired on its surface. Next, the material 2 is packed up to the top end, and the rubber mold 1 is closed and after pressure molding, the molding is fired to allow the material 5' to evaporate and burn out, thereby forming a slit 8'. In this case if a urea modified phenolic resin or the like modified with a urea resin or the like of extremely less fixed carbon is used as the slit forming material, the residual carbon remains less in the slit 8'. |
