| 摘要 |
PURPOSE:To improve the natural rate of perforation of the titled packing material by killing of a molten steel static pressure and to decrease the use of the packing material to be used by incorporating combustible material pieces into the upper layer of a high melting point packing material and/or low melting point packing material. CONSTITUTION:The layer of the paper pieces-contg. high melting point packing material 26 into which corrugated board pieces, etc., as the bulky combustible material pieces are incorporated is provided in the upper layer part of the high melting point packing material 24 which does not sinter even when the agent contacts the molten while a sliding nozzle is open. Further/or the layer of said proper pieces-contg. low melting point packing material 28 is provided in the lower layer part of the low melting point packing material 30 which sinters when the agent contacts the molten metal. The sintered layer is made brittle by the spaces generated in the sintered layer and the killing of the molten steel static pressure is easily broken by the above-mentioned constitution. |
