Method and of apparatus for manufacturing a bent product

摘要

A method of manufacturing a bent product, wherein, even if the product must be provided with bends with various shapes or the product must be formed by bending a metal material having high strength, the method can perform such bending with high working accuracy and can obtain a large bend angle without impairing the surface properties of the metal material. A steel pipe (1) is supported at a first position (A) while being fed in the longitudinal direction of the steel pipe (1), the steel pipe (1) being fed is partially heated at a second position (B), and the heated portion of the steel pipe (1) is cooled at a third position (C).  Then, the position of a clamping means (15) for clamping the steel pipe (1) in a region (D) located downstream of the third position (C) is changed, in a work space including an empty space located on the upstream of the third position (C) in the feeding direction of the steel pipe (1), to a three-dimensional direction including the feeding direction of the steel pipe (1).  Thus, bending moment is applied to the heated portion of the steel pipe (1) to produce the bent product having three-dimensionally bent portions provided intermittently or continuously to the steel pipe (1) in the longitudinal direction thereof.