| 摘要 |
PURPOSE:To decrease the sticking of molten metal to the inside surface of a vacuum vessel and to extend the life of a refractory material having specific properties in a titled device for sucking the molten metal up into the vacuum vessel by constituting the vacuum vessel of the above-mentioned refractory material and providing an induction coil to the circumference thereof. CONSTITUTION:The vacuum vessel 2 is a cylindrical vessel which consists of the refractory material which has electrical conductivity and good wettability with the molten metal. Since this material is required to maintain vacuum, the material is dense and has air permeability. More specifically, graphite used for an electrode, etc., is suitable and carborundum and SiC, etc., are also usable. The opened bottom end of the vessel 12 is directly immersed into the molten metal 11 and the circumference is enclosed with a heat insulating material 13. A coil 14 for induction heating is mounted to the outside circumference thereof. Induction current flows to the vessel 12 and the vessel 12 itself is heated when the coil 14 is first energized. The molten metal 11 in a ladle 10 rises in the vessel 12 when the inside of the vessel 12 is evacuated to a vacuum through a vent hole 12a at the top end. Since the vessel 12 is heated at this stage, there is no possibility of damage to the vessel by thermal impact. A stirring effect is generated in the molten metal 11 by the coil 14, by which the rate of degassing is improved. |
