| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel pipe, and to provide such a facility line for manufacturing the steel pipe as to be suitable for the manufacturing method. SOLUTION: The method for manufacturing the steel pipe includes subjecting a base steel pipe to heat treatment and subsequent cooling treatment. The cooling treatment includes using a cooling means of a cooling roll which comprises a plurality of metallic rolls disposed around an almost whole outer surface of the base steel pipe, so as to be contactable with the outer surface. Thereby, a steel pipe which does not warp even when rapidly cooled can be easily and stably manufactured. In addition, steel pipes having various characteristics can be freely and stably made from a base material having the same composition. The cooling rolls are preferably disposed in a plural stages. Cooling by water may be added into the step of cooling by the cooling roll. The inside of the metallic roll is preferably cooled by a refrigerant. Diameter reduction rolling may further be applied to the steel pipe after heat treatment. COPYRIGHT: (C)2008,JPO&INPIT
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