METHOD FOR MANUFACTURING SHAPED STEEL THE CROSS-SECTIONAL SHAPE OF WHICH CHANGES IN THE LONGITUDINAL DIRECTION, AND ROLL FORMING DEVICE.

摘要

A roll forming device, for roll forming for the purpose of manufacturing shaped steel the cross-sectional shape of which changes in the longitudinal direction, is equipped with: first die rolls having an annular ridge part the cross-sectional shape of which changes in the circumferential direction; second die rolls having an annular groove part the cross-sectional shape of which changes in the circumferential direction; and a drive device for the first die rolls and the second die rolls. A clearance is provided at the side surfaces of the annular ridge part of the first die rolls, across the entire circumference in the circumferential direction, such that the gap with respect to the side surfaces of the annual groove parts of the second die rolls widens inward in the radial direction.