| 摘要 |
PURPOSE:To prevent clogging of a nozzle and to reduce production cost by forming a pipe at position easily developing the clogging of flow passage by ceramic single substance of BN as main component or the inner and outer faces of the pipe by double construction of the ceramics. CONSTITUTION:The flow passage is formed by dividing into plural number of pipes and the pipes are joined to produce one piece of the flow passage. The position of the pipe easily developing the clogging of flow passage is formed by the BN pipe made of BN as the main component. Or, the double constructed pipe is formed by inserting the ceramic pipe 3 made of BN as the main component in the inner face and backing up the outer side by the other ceramic pipe. As BN component naturally has difficult property to wetting with the molten steel, the clogging of the nozzle caused by sticking of the molten steel or oxide is prevented by this construction. As the expensive BN ceramic is locally used only at the necessary position, the production cost is reduced. |
