| 摘要 |
PURPOSE:To produce a firm CO2 mold of less amount of free moisture by adding sodium silicate of a specific molar ratio and a selected dehydration accelerator to raw material sand. CONSTITUTION:Silical sand of about 100 meshes and 0.3-1wt.pt. one or more kind of Fe-Si alloy powder, Ca-Si alloy powder and Al powder of about <=10mu are added, and 4-7% sodium silicate of >=2mol ratio is added, and these the kneaded to form a mold. Thence, CO2 gas is blown to make a CO2 mold. At this time the powder of the alloys etc. added acts are a dehydration accelerator, thus the CO2 mold of less amount of free moisture with increased strength and pressure resistance is obtained. |
