PURPOSE: To produce a cast billet having good surface and no surface crack even in the deformed cast bullet having complicate shape by arranging a cooling device for directly cooling the cast billet with cooling water independently to the cooling in a mold.
CONSTITUTION: Piping is connected with connecting members 16, 17 and cooling water is made to flow in the lower step mold 11b and also flowed in cooling piping 15. Thereafter, when the molten metal is poured into a space surrounded in the inner surface 12 of the mold 11, the molten metal is brought into contact with the inner surface 12 of the mold 11 and cooled to form the solidified shell. The cast billet is successively drawn out downward from a mold 11. Then, the cast billet is directly cooled with cooling water by receiving the injection of the cooling water from the coding water piping 15. In the mold 11, the extremely weak cooling is given, and after the cast billet comes out from the mold 11, the intense cooling is given by the cooling water and the cast billet is perfectly solidified. Therefore, it is prevented that cold shut-like ripple caused by solidification of the cast billet in the mold 11 is formed. As the cast billet coming out from the mold 11 is directly and forcedly cooled with the cooling water, the development of the surface crack can be prevented.
MATSUOKA SUSUMU
MIKI TAKAHIRO
HAYASHI KENJI
