| 摘要 |
PURPOSE:To cast continuously hollow stock by applying exothermic powder to the inside of a casting mold in the end period of continuous casting to delay the solidification of the molten steel meniscus thereby preventing the bending of a core owing to a difference in thermal expansion between the core and ingot and decreasing considerably the eccentricity of the core. CONSTITUTION:The molten steel supplied 9 from a ladle 8 is supplied together with the core 2 into the casting mold 3. The core 2 is rotated at the controlled speed so as to apply the tensile force to generate the stress below the permissible stress thereof to the core 2 against the downward tensile force by pinch rolls 7 for drawing a hollow round bloom 1. The buckling of the core 2 arises from the formation of the solidified shell at the meniscus of the molten steel in the mold 3 at the end period of such continuous casting and therefore the precedent formation of the solidified shell is suppressed by the following method until the casting is completed: The exothermic powder is applied to the inside of the mold 3 at the above-mentioned period to prevent the bending (eccentricity) of the core 2. The powder contg., for example, Al, Al2O3, SiO2, Fe2O3 and C respectively at prescribed ratios is used for the exothermic powder. |
