PURPOSE: To eliminate non-metallic inclusion and to reduce defect in the product by arranging the metal sheet to a hanging member at intermediate position between a clad material and top part of an ingot and further screwing the hanging member into the clad material.
CONSTITUTION: Plate-like heat insulating material 2 is set to the inner wall 4 surface of a mold 1 and also the metal sheet 8 for melting together with base molten metal is almost horizontally fitted to the hanging rod 9. Next, the contacting part 12 between the hanging rod 9 and the clad material 3 is screwed. Invasion of sprinkling agent for insulating heat of the hot-top charging on the top part of the ingot is prevented by setting the metal sheet 8 and as the connecting part 12 is screwed, effect of the flux is eliminated. By this method, the cause of development of the non-metallic inclusion at the part corresponding to the top part of the ingot is removed, and the developments of the defect caused by this and interface defect of oxide caused by invasion of the air are prevented. Therefore, the defect of the product is reduced.
KAWARADA AKIRA
KITAOKA HIDENARI
