| 摘要 |
PURPOSE:To prevent cracking in the inner face of a hollow cast billet and to obtain the sound hollow cast billet by enclosing as inserting a core of metallic pipe as changeable to its diameter into the case billet in a mold. CONSTITUTION:The metallic core 1 has a construction, which makes a metal plate 12 as pipe-like by winding to one round or more without any sticking by welding or adhesion at the end parts 10, 11 thereof. This metallic core 1 is continuously supplied at the center part of mold 2 as passing through the molten metal 6 in a tundish 5 connected with a brake ring 4 at the upper part of mold 2. On the other hand, the molten metal 6 is poured at between the metallic core 1 and the mold wall via the tundish 5 through a pouring nozzle 8 and drawn as one body together with the hollow cast billet and the metallic core from the lower part of mold 2. Shrinkage force developing on the solidified shell of metallic core surface is released and relieved by reducing the diameter of metallic core, to prevent development of cracking in solidified shell. |
