| 摘要 |
PROBLEM TO BE SOLVED: To secure the remaining thickness of a porous brick even after oxygen-cleaning by blowing oxygen to metal solidified in the inner part of a gas blowing upper nozzle, generating heat, melting the metal and blowing a specified flowing quantity of inert gas from the porous brick disposed in the upper nozzle when the metal is removed. SOLUTION: After using the upper nozzle 23, for using this nozzle again, steel 25 solidified in the upper nozzle 23 is melted and removed. For example, oxygen is blown from a pipe 26 to the steel 25 solidified in the upper nozzle 23 fitted to the upper part of an opening/closing nozzle 22 in a tilted tundish 21, and heat is generated with an oxidizing reaction and the steel 25 is melted and removed. At this time, a molten iron oxide is produced and slag is infiltrated into the upper nozzle refractory, particularly the porous brick, and the refractory is eroded. In such a case, inert gas such as Ar of 5-30 l/min is blown from the porous brick disposed in the upper nozzle 23 to prevent the infiltration of the slag into the porous brick.
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