| 摘要 |
PURPOSE:To give a good elongation of a columnar crystal to a casting product and to prevent the generation of a casting defect by a crack, etc., as well by combining the casting sand having a comparatively larger thermal diffusion and a small metal piece at an optional rate and molding the mold in the necessary shape. CONSTITUTION:The casting sand having a comparatively larger thermal diffusion and a small metal piece are combined at an optional rate, preferably at the rate of about 40:60 and the mold in the necessary shape is molded. A zircon, chromite sand, carborundum grain can be used for the casting sand and for the small metal piece the cut piece of a steel material (cut piece of steel wire) and steel ball can suitably be used. When a molten metal is poured by using this mold, enough length and fineness are given to the columnar crystal by giving the directivity controlled in the solidifying direction of a casting product, the expansion and contraction accompanied by the high temp. and cooling at casting time are stabilized less, so the defect generation of a crack, etc., is prevented.
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