| 摘要 |
PURPOSE:To diffuse the air introduced into a molten steel in all directions and to obtain a smooth ingot having less ruggedness by dipping a core material which is formed with recesses each having a limited groove size to a grating shape on the surface and is limited in the total area of the projecting parts into the motlen steel and sticking solidified layers thereto. CONSTITUTION:The recesses 4 are formed to the grating shape onto the surface of the core material 1 and the recesses 4, i.e., grooves, are vertically and horizontally connected. The width of the recesses 4 is made <=2.0mm, the total area rate of the projecting parts 5 is made <=10% and the total area rate of the recesses 4 is made >=90%. The gas such as air captured at the boundary faces is thus diffused through the grooves in all directions, by which the air gap is prevented and the molten steel is allowed to contact only with the projecting parts 5. The contact area is decreased and the heat transmission is relieved. |
