| 摘要 |
PURPOSE:To obtain a metallic mold for casting, where good gas venting effect is expected and high quality casting can be manufactured by applying inclination to a gas venting groove communicated and opened to the air outside of the metallic mold from cavity side so as to come to smaller flowing cross sectional area as going to outside. CONSTITUTION:The slowing cross sectional area (a) at opening side to the air is formed to smaller than the flowing cross sectional area A at the cavity side of the gas venting groove 4. When molten metal after filling up in the cavity reaches the gas venting groove 4, semi-solidification starts. The conventional selective molten metal flowing, which runs out while spreading the semisolidified part with back pressure, is forcedly squeezed with inclined face changing squeezed force utilizing the inclined face in sloping direction to restrain running out force. By this method, it is prevented that the molten metal runs out and as length of the gas venting groove 4 can be shortened, solid oil developed in the groove 4 can be easily blown out and the perfect gas venting is achieved and the casting without blow hole, rippled surface, etc., is obtd. |
