ROLL FORMING METHOD FOR METAL MATERIAL AND ROLL FORMING DEVICE FOR METAL MATERIAL

摘要

This roll forming method for a plate-shaped metal material (M'), of which the plate thickness changes in the longitudinal direction, is characterized by comprising multiple stages of roll forming steps for: conveying the metal material (M') to between multiple pairs of forming rolls (RA1-RA13, RB1-RB13); and forming the metal material (M') in stages such that the shape of a cross section orthogonal to the longitudinal direction of the metal material (M') becomes a predetermined shape including a curved corner section (CR). Among the multiple stages of roll forming steps, in the successive roll forming steps in one or multiple stages including the last stage, the corner section (CR) is formed by the pairs of forming rolls (RA11-RA13, RB11-RB13) which have corner section curvature radiuses (r3-r5) smaller than a target curvature radius (rt) of the corner section (CR) of the metal material (M').