| 摘要 |
PROBLEM TO BE SOLVED: To enable a core pin to keep heat in a prescribed range for a long time with simple and unexpensive constitution and to enable it to operate the temp. distribution by forming a cooling water passage in the inner part and a heat insulating space between the heat keeping surface where the heat keeping is partially needed and the cooling water passage. SOLUTION: A core pin (core pin for casting) 5 is constituted with an outer pin 21 and an inner pin 22. Cooling water enters from a cooling water introducing passage 241 in the inner pin 22 and discharges from a cooling water discharging passage 242. A portion of the heat keeping surface C of the core pin 5 needs the heat keeping on the progress of solidification in a casting. In the portion except the heat keeping surface C, the outer pin 21 is brought into direct contact with the inner pin 22 and the heat of molten metal is delivered to the cooling water through the outer pin 21 and the inner pin 22. In the inside of the heat keeping surface C, a groove 213 in the circumferential direction of the outer pin 21 is formed and separated from the inner pin 22 and a gap space (heat insulating space) D is formed to insulate the heat.
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