| 摘要 |
PURPOSE:To relieve the abrupt thermal change of molten metal, reduce the thickness of a coarsened crystal region and decrease the occurrence of surface defects by providing specific grooves on the inside wall surface of a mold in contact with molten metal, and cooling and solidifying the molten metal while suppressing heat transmission. CONSTITUTION:Multiple grooves 11 are provided, as inside wall longitudinal grooves, in a pouring direction on the inside wall surface of a mold 10 to be put in contact with molten metal, over the entire circumference thereof, at 1-5mm. groove pitches and 0.3-3mm. depth of the grooves. When the molten metal is supplied, it contacts the crest parts 11a of the grooves 11 on the inside wall surface of the mold, whilist it cannot enter the trough parts 11b, and air gaps are formed there; therefore, the heat transmission of the entire part of the mold is effectively suppressed. Since the lubricating oil is surely conducted to the grooves 11 through lubricating oil grooves 12, the uniform distribution of the supply is accomplished, and since the lubricating oil is conducted down to the lower part of the solidified shell through the parts of the air gaps, the surface of the cast ingot is further improved. |
