| 摘要 |
PROBLEM TO BE SOLVED: To easily form a tube having a step in level by disposing a formed body of the different portion in level on the inner part of a cylindrical metal frame, rotating the cylindrical metal frame after heating, pouring molten iron to execute the casting, integrating with the formed body and pulling out the tube having the difference in level from the cylindrical metal frame after solidifying. SOLUTION: A formed body 1a is set at the tube end portion in the inner part of the cylindrical metal frame 4, and this is heated to high temp. Successively, the metal frame 4 is rotated, and the molten iron 12 is poured into the cylindrical metal frame 4 to execute the centrifugal casting. At this time, the molten iron 12 is spread in the layer state in the inner surface of the metal frame 4 with the centrifugal force and brought into contact with the base part of the formed body 1a in the formed body 1a portion. Since the formed body 1a is preheated, the base part thereof is molten with the heat of the molten iron 12 and integrated with the molten iron 12. Thereafter, the formed body 1 is slowly cooled with cooling water W supplied into a water jacket and after solidifying, the formed body 1 is pulled out. At this time, the diameter of the end part of the tube 1 is shrunk to the inside of the tube, but since there is no projection for forming this in the inner surface of the metallic frame 4, the formed body 1 can be pulled out easily.
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