PURPOSE: To continuously and smoothly manufacture the hollow billet by drilling the cooling tube passage opening to one end side at the core, and inserting the coolant supplying tube which extends from one end of the cooling tube passage to the other end part and opens at the other end part.
CONSTITUTION: The tubular mold 1 is cooled by supplying the coolant from the mold coolant supplying tube 7, the core 2 is arranged by the same axis in the casting mold 1. The molten metal C is supplied from one end side of the tubular space formed between the casting mold 1 and the core 2, and the hollow billet is manufactured by cooling and solidifying it in this space. Then, the cooling tube passage 21 which is entered from one end and opens to the same one end only is set in the core 2. Also, the core coolant supplying tube 23 which extends from the one end of the cooling tube passage 21 to the other end part and opens at this other end part is inserted. Therefore, the hollow billet without generating a segregating layer can be obtained.
FURUSHIBA YUTAKA
SUGAWARA YUKIO
KOIDE MASATO
SHIDARA FUSAO
