| 摘要 |
PURPOSE:To improve natural opening ratio of a steel discharging hole by arranging a cover at top part of cylinder and packing different kinds of silicas as multiple layers in inner part of the cylinder. CONSTITUTION:In the plug for preventing clogging, the paper cylinder 41 is arranged to an upper nozzle 33. The cover 42 is put on the top part of the paper cylinder 41 and three different kinds of the silica sands are packed into inner part of the cylinder 41 as three layers. The silica sand 43 having low m.p. and fine grain for upper layer, the silica sand 45 having high m.p. and coarse grain for lower layer and the silica sand 44 having intermediate properties between the above silica sands 43, 45 for middle layer, are selected. At the time of making opening state of the rotary nozzle 20, the molten steel is discharged from the upper nozzle 33 through lower nozzle 34. By this method, the natural opening ratio of the steel discharging hole is improved. |
