| 摘要 |
PURPOSE:To prevent cracking by combining the outside circumferential part of the nozzle body and the nozzle body part with the specific dissimilar refractories and keeping the range of the difference in the coefficient of thermal linear expansion thereof in the specific range. CONSTITUTION:In the two layer type immersion nozzle, the coefficient of thermal linear expansion at the outside circumferential part of the nozzle body is made equal to or higher than that of the nozzle body and the difference thereof 0.15% or under in the rate of thermal linear expansion. Compounding for the nozzle body comprises containing alumina 35-75%, flake graphite 30-10%, molten quartz 25-8%, metal silicon 8-1%, silicon carbide 15-1 and zircon 5-1% based on weight and kneading these powder granular raw materials together with carbonaceous binders. Compounding for the outside circumferential part of the nozzle body comprises containing zirconia 66-85%, flake graphite 35-10%, metal silicon 8-1% and silicon carbide 15 to 1% based on weight and kneading these powder or granular raw materials together with carbonaceous binders. |
