| 摘要 |
PURPOSE:To prevent generation of the shrinkage cavity and blowhole defects of a casting by packing a molten Al alloy under pressurization at a low speed into a metallic mold cavity, solidifying the local part of the molten metal by high pressurization and subjecting the solidified part to plastic working. CONSTITUTION:A local pressurizing core pin 8 connected to a hydraulic cylinder 11 for locally pressurizing the molten Al alloy in the metallic mold cavity 5 is provided and a slide plate 9 is disposed to a metallic mold 6. After the molds 6, 7 are clamped, the molten Al alloy is supplied into a sleeve 1 and a tip 3 is advanced at a low speed to pressurize and pack the molten metal through a gate 4 into the cavity 5. The molten alloy in the cavity 5 is then pressurized by the pin 8 to solidify the molten metal; thereafter, the slide plate connected to the cylinder 11 is retreated so that the solidified part is plastically worked to a required shape. Since the local pressurization is executed after the low speed packing of the molten metal into the cavity, the generation of the shrinkage cavity and blowhole defects of the casting is prevented.
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