| 摘要 |
PROBLEM TO BE SOLVED: To obtain both of the strength and the gas ventilation of a mold, in a green sand mold for small size casting used as a drag. SOLUTION: In the one to be used as the drag 2 in the green sand mold 1 for small size casting which is formed by compressing a green sand S into the inside of a casting flask 12, the upper surface 4 formed along the upper end ridge of the molding flask 12 and a forming recessed part 5 formed so as to be recessed on the upper surface 4, are provided. A green sand layer 19 constituting the drag 2 is connected with the molding flask 12 in the lower surface of the green sand layer at a position apart upward from the lower end ridge. On the lower surface of the green sand layer 19, a space 23 is formed at the lower part of the green sand layer 19 in the molding flask 12 so as to form a bulging part 12 bulged to the lower part at the position corresponding to the forming recessed part 5. The inclining angleθof the inclined surface 18 forming the bulging 22 is made in the range of 40-50 deg. to the upper surface 4.
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