| 摘要 |
<p>PURPOSE:To prevent the generation of solidified cover and internal defect of inclusions, etc., by charging molten powder at the initial stage of casting and adding fine powder before the drawing speed of a cast slab reaches to the stationary speed. CONSTITUTION:The molten powder is charged at the stage when the molten steel surface is resin by pouring the molten steel and reaches the discharging hole of an immersion nozzle and further, the discharging hole becomes below the molten steel surface. The charged molten powder is floated up on the molten steel surface newly poured and covers the molten steel. Thereafter, the granular or fine powder is added on the previously charged molten powder. By this addition, the previously charged molten powder surface layer is covered and insulated to heat. By making the layer thickness of the molten powder 20mm at the time when the drawing speed reaches to the stationary speed, carburization is prevented.</p> |
