PURPOSE: To efficiently preheat a nozzle in a short time and to excellently heat-insulate the nozzle after preheating by providing plural projecting parts in the inside of a cylindrical formed body.
CONSTITUTION: Plural projecting parts 2 are provided to be opposed with each other at the position in the inner part of the ceramic fiber-made cylindrical body 1 to form a heat insulating material 1 for preheating. The projecting parts 2 are formed in a stripe-state having a prescribed width in the vertical direction. This heat insulating material 1 is used by insert-fitting from the lower part of the molten steel pouring nozzle 4. In this case, the length L between the insides of the projecting parts 2 formed in the inner surface of the heat insulating material 1 is preliminarily specified and formed so that the tip parts of the projecting parts 2 abut on the outer peripheral surface 5 of the molten steel pouring nozzole 4. Further, by properly selecting the height of the projecting parts 2, the gap 6 formed between the outer peripheral surface of the nozzle 4 and the heat insulating material 1 is constituted so that flame can sufficiently be passed. For example, the length of the gap 6 is made in the range of 2-10mm.
SUGIURA SADANOBU
IIBASHI TETSUYA
TANIZAWA YOSHINORI
ARIMOTO TERUMI
SUMITOMO METAL IND
Next Patent: JPS6344127