Vacuum casting method.

摘要

In a vacuum casting method, a molding cavity (6) is reduced in pressure to a vacuum, and when a gate (10) is opened, a molten metal which has been raised to a molten metal retaining dome (8) is charged into the molding cavity (6) at a high speed. When a portion of a molten metal held in a molten metal holding furnace (22) is raised to the molten metal retaining dome (8) via a stalk (20), (a) the rising speed of a portion of the molten metal (24) is set at 5 - 10 cm/sec, or (b) the rising speed is varied between an early stage of the rising motion and a later stage of the rising motion. In the latter method, the rising speed at the early stage of the rising motion is set at a speed higher than 10 cm/sec, while the rising speed at the later stage of the rising motion is set at 5 - 10 cm/sec. Due to the rising speed control, air involvement by the rising molten metal (24) is effectively prevented.