| 摘要 |
PURPOSE:To obtain a casting mold which assures prescribed strength of a casting by providing projecting parts in the thickness direction on the side where the accuracy of expendable split patterns for precision casting is not required thereby preventing the intrusion of a slurry liquid into the joint space in the stage of forming a coating layer and eventually the formation of the thin-walled part of the casting. CONSTITUTION:The projecting parts 2A, 2B projecting in the thickness direction of circumferential walls 1a1, 1b1 are formed on the inside circumferential side of the joint parts 1a, 1b of the split patterns 1A, 1B mentioned above where the accuracy is not required. An inorg. adhesive agent 3 is coated on the joint surfaces 1a2, 1b2 of the patterns 1A, 1B and thereafter the slurry liquid and further molding sand are coated thereon and are dried to form the coating layer 3. The patterns are then subjected to a heating treatment by which the patterns are expended and the casting mold 6 having a space 5 is formed. Even if the slurry liquid introduces into the joint space 8 in the stage for forming the layer 4, the depth lX of the space 8 is kept within the projecting length lX1 of the projecting parts 2A, 2B and the intrusion of the slurry liquid beyond said parts is prevented. |
