| 摘要 |
PURPOSE:To produce a long-sized circular columnar steel ingot with good workability by moving the mold placed on a bottom casting molding board consisting of a lower molding board for introducing molten steel and an upper molding board having a recess for detaining of the steel ingot upward in accordance with the formation of the solidified layer of the molten steel. CONSTITUTION:A mold 12B is placed on a bottom casting molding board consisting of a lower molding board 8 and an upper molding board 10B, and molten steel 2 is charged up to below a sleeve 22 for heat insulation of a riser. The surface of the molten steel is insulated of heat with a covering material 24 for heat insulation. In the stage when a solidified layer 26 is formed on the outer side of the molten steel 21, the mold 12B is moved upward by an elevating device 20 via an upward and downward moving wire 16. The layer 26 is detained by a recess for detaining of a steel ingot. Only the mold 2B ascends to form a space freshly, and the steel 2 is charged into said space. The same operation is repeated up to a prescribed height. In the final stage of casting, the steel 2 is charged up to the sleeve 22 and the surface of the molten steel is insulated of heat with a large amt. of the material 24 to maintain the head part of the steel ingot in a molten state for a long time, following to which the molten steel is allowed to solidify. |
