| 摘要 |
PURPOSE:To improve the lubricity of the inside wall surface of a mold of a hot top casting device with less lubricating oil, to decrease the number of polishing steps for the mold surfaces and to improve the quality of the surface of cast ingots by forming a chrome plating layer on the inside wall surface of the mold. CONSTITUTION:A direct cooling mold 22 of a cylindrical shape made of pure copper is provided below a receiving tank (hot top) 20 made of refractories for molten metal, and the circumferential bottom end part of the tank 20 overhangs from the inside wall surface thereof to the inner side, thereby forming an overhange part 24. A hard chrome plating layer 40 of a prescribed thickness is formed over the entire circumferential surface of the inside wall surface of the mold 22 in contact with molten metal. When the molten metal 21 is supplied, a molten metal column is formed on a bottom plate 42 by the inside wall surface of the mold 22 and the tank 20, and said column is primarily cooled via the layer 40 by the cooling water flowing through the chamber 26. Thereafter, the molten metal is cooled secondarily wit the water ejected through slits 30 and is removed as a cast ingot 32. During this time, lubricating oil is supplied continuously from a supply passage 38 through a well 34 and a groove 36 to the inside wall surface of the groove 22. |
