| 摘要 |
PURPOSE:To provide a casting mold which prevents the replenishment of a molten metal from a product part to a sprue upon shrinkage of a sprue provided in the lower part by solidification and prevents the formation of a shrinkage cavity in the product by providing a gate in the joint part between the product part and the sprue for the purpose of solidifying the molten metal in said part earlier than the molten metal in the sprue. CONSTITUTION:A gate 11 having the sectional area smaller than the sectional area of a sprue 3 and having the shape forming the surface on both or one side with the same curve as the curved surface in a product part 10 is provided in the joint part between the product part 10 and the sprue 3. A notch 12 may further be projected into said curving shape on said surface. If a molten metal is cast by using a casting mold 7 constituted in the above-mentioned way, the molten metal solidifies eariler at the gate 11 than in the sprue 3 and therefore if the mold 7 is pulled upward from the molten metal surface at the point of this time, the molten metal in the sprue 3 is discharged by gravity. Only the gate 11 remains in the mold 7. Even if the pulling up period delays and the sprue 3 solidifies, the solidified gate can be broken in the part of the gate and the trace of removing the gate is flush with the curved surface of the casting. The effect is much better if the notch 12 is provided. |
