| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw coupling type propelling pipe structure capable of reducing damage due to friction with sediment or the like in propulsion and reducing the resin material cost and construction cost of a resin coating. SOLUTION: A screw coupling type propelling pipe 10 is formed by screw- joining an outer resin coated steel pipe 10a coated with resin 13 and an outer surface resin coated steep pipe 10b. The resin coating of a screw part 11 outer surface of a succeeding outer resin coated steel pipe 10a with respect to the propelling direction is a resin coating having the same hardness as that of the resin coating 13 of the outer surface resin coated steel pipe 10a, and on the other hand, a resin coating 14 having a hardness higher than that of the resin coating 13 of the screw part 11 outer surface of the outer surface resin coated steel pipe 10a is applied to the screw part 12 outer surface of the preceding outer surface resin coated steel pipe 10b. A resin coating having a higher hardness is applied only to a portion liable to be damaged in propulsion, so that the resin coating material cost and the resin coating construction cost including off-line can be reduced.
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