| 摘要 |
PURPOSE:To improve the heat resistance of a casting mold by adding a small amt. of a composite oxide, carbide, boride, etc. combined with a new ceramic material to silica sand in the stage of adding starch in a powder or glue state to the silica sand and kneading the same. CONSTITUTION:The composite combined material of the new ceramic material consisting of the oxide such as silica or zirconia, carbide such as boron carbide or titanium carbide, boride such as titanium boride or chromium boride, nitride such as titanium nitride or hafnium nitride is added to the silica sand at 0.1-1.0% ratio. A mineral material such as graphite is further added at 0.1-0.5% to the silica sand and is kneaded together with the starch. The moisture for the starch is determined to an adequate value according to the kind of the starch. The heat resistance of the dry starch mold for casting is improved by the above-mentioned method. The fluidity and heat resistance of molding sand are much improved by the addition of the graphite. |
