| 摘要 |
PURPOSE:To produce a hollow billet having good dimensional accuracy without trouble during casting by providing a cooling water spray nozzle to the bottom end of a water-cooled core and cooling directly the inside circumferential surface of the hollow billet by the cooling water from said nozzle. CONSTITUTION:The body of the water-cooled core 3 is made into the double- pipe construction consisting of a central flow passage 3a on a cooling water introducing side communicating with said body at the bottom end thereof and an outside annular flow passage 3b. A spray pipe 9 is penetrated in the passage 3a and the nozzle 9a is provided to the projecting top end thereof. The water is injected from said nozzle 9a to the hollow inside circumferential surface of the billet to cool directly said surface with the water and to form a secure solidified shell. A passage for releasing the cooling water is provided to a dummy bar 10 for drawing the billet. More specifically the passage is made into such construction in which plural pieces of detaining pieces 11 such as bolts are attached to the top end of the bar 10 and that a through-hole 12 for accepting the bottom end of the core 3 and the extension thereof in the axial direction are communicated with a water drain port 13 provided to the side part. |
