| 摘要 |
PURPOSE:To prevent the intrusion and solidification of a molten metal and to prevent surely nozzle clogging by spraying coating refractory powder contg. org. material powder which hardens while softening when applied with heat on the surface of the refractory powder packed into the nozzle in the base of a vessel for the molten metal and forming a uniform bound carbide layer on the above-mentioned surface. CONSTITUTION:For example, silica sand powder 6 as the refractory powder is charging and packed from the upper part of a ladle 1 by a charging chute into the nozzle 5 provided to the base 2 of the ladle 1. The powder mixture formed by mixing a prescribed ratio of bittern powder with the refractory powder consisting essentially of the silica sand is coated atop the silica sand powder 5. The coating refractory powder 7 contg. 3-50% org. powder (e.g.; sugar powder) is coated thereon to a prescribed thickness. The carbonization bond is attained with the former while the powder 7 is softened and fluidized by utilizing the preheating of the ladle 1 to 700-800 deg.C by a ladle preheating burner and the carbonization bond is attained with the latter by the sensible heat of the ladle 1 at about 300 deg.C. As a result the intrusion, solidification and sintering of the molten metal into the nozzle 5 are suppressed and the nozzle clogging is surely prevented. |
