| 摘要 |
PURPOSE:To facilitate control of texture and material strength of a casting and increase rotation of molding flask by increasing cooling speed of a casting poured in a reduced pressure molding mold by flowing of refrigerant to a pipe burried in the mold. CONSTITUTION:A suction air chamber 2 of a metal frame 1 for reduced pressure molding is connected to a vacuum pipe through suction air outlet 3. An undulatory cooling pipe 4 in the frame 1 is connected by reinforcing members 5 and the end parts 6 are supported by a stopper 7 and at joints 10 which are at refrigerant inlet 8 and outlet 9. The frame 1 is set on a pattern when molding and in this state the pipe 4 is kept horizontal. After molding, the lower die is reversed. At this point of time, however, the pipe 4 is completely burried and fixed in molding sand. During the process of pouring molten metal in the mold and cooling the casting 12, a cooling medium such as water, air etc. is let flow. Spaces between sand particles are negative pressure during continuation of suction until completion of solidification and cooling effect is small. After stopping suction, however, the effect is large enough to compensate for delay in time. |
