PURPOSE: To uniformly cool the whole length of a cast tube by cooling over the whole length of the cast tube after pre-cooling a receiving hole of the cast tube, which is cast as thick thickness compared with the barrel part, and after that, post-cooling the receiving hole.
CONSTITUTION: It is received in a control device 20 that molten metal is cast in inner part of a mold 1, and the cooling water is injected into the inner part of the receiving hole 4 from a water spray nozzle 8. When water spraying time reaches to the prescribed time, a cooling water pipe 5 is projected into the inner part of the receiving hole 4 and the water spray nozzle 8 is shifted along the pipe axial center direction and after passing the prescribed time, the pre-cooling with a first step spraying is completed. Successively, a cooling water supply device is set into the inner part of the cast tube 2 from the opposite side of the receiving hole 4 and the cooling water is sprayed to over the whole length of the cast tube to cool to the prescribed temp. Then, at the time of completing the second cooling, the water spray nozzle 8 is sprayed while shifting in the inner part of the receiving hole 4. Successively, this third cooling is executed for the prescribed time, to complete the post-cooling. Therefore, the receiving hole 4 receives more cooling action than the barrel part 4 with the pre-cooling and the post-cooling, and the receiving hole 4 is cooled at the equal temp. as the barrel part 3.
INOUE TOSHINAGA
NAKAKUBO KOJI
TASHIRO TSUTOMU
UEMAE KOICHI
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