| 摘要 |
PROBLEM TO BE SOLVED: To provide a stretch-reducing method for a pipe capable of effectively preventing torsion of a material that happens due to an asymmetrical contact of the material to a roll. SOLUTION: A displacement of a peripheral direction of a pipe 1 is restrained by mounting a guide 4 between at least one pair of adjoining stands #i, #i+1. The guide is preferably a roll-type guide. The ratio between a distance 1 from a mounting position of the guide to a position of a stand at an outlet side of the guide and the outside diameter d of the pipe restrained by the guide is preferably not more than an index Xc that is defined by the following formula (1) Xc=α.(d/t).Δθn/180, where t: a wall thickness of the pipe, n: the number of rolls of the standΔθ: a phase difference between the stands wherein the guides are mounted (unit: angle),α: a factor depending on deformation resistance of the pipe, the quality of the material of the pipe and the diameter of the pipe.
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