| 摘要 |
PROBLEM TO BE SOLVED: To surely manufacture a bending member in which a bending radius of a bending part is small, for example, in 100 mm or less and a bending angle of the bending part is also large, for example, in 90° or more, even when a bending work speed in 3DQ is high in 60 mm/sec or more.SOLUTION: A hot bending workpiece having a bending part quenched by imparting the bending moment to a deformation resistance reduction part formed by partially heating to an Acpoint or more in the axial direction of a steel pipe 1, is manufactured while sending the steel pipe 1 to a high frequency induction heating coil 5 for heating the steel pipe 1 and a first water-cooling device 6-1 for cooling the steel pipe 1, in the axial direction. A second water-cooling device 6-2 is arranged on the downstream side in the sending direction of the steel pipe 1 to the first water-cooling device. The second water-cooling device 6-2 is oppositely arranged by arranging the steel pipe 1 in-between, and comprises a pair of headers 10a and 10b having a plurality of rows in parallel by turning a nozzle 11 for injecting cooling water toward the steel pipe 1, to the advancing direction of the steel pipe 1. The nozzle 11 in the pair of headers 10a and 10b is also arranged in substantially parallel to a plane including a predetermined bending direction.SELECTED DRAWING: Figure 4 |
