FIELD: process engineering.
SUBSTANCE: invention relates to machine building, particularly to metal forming, and can be used for making decorative articles, say, volutes and monograms for arches, etc, from shaped tubes. Prior to bending, the workpiece cross-section is changed to make stiffness ribs by rolling tube wall part inwards at tube sides. Note here that rolling tube wall part rib height and width are selected subject to wall depth. Stiffness ribs are produced by forming discs with cross-section shape that ensures the required rolling tube wall part rib height and width.
EFFECT: higher quality.
9 cl, 7 dwg
