METHOD OF LARGE-DIAMETER PIPES STEP MOLDING Russian patent published in 2019 - IPC B21C37/06 

FIELD: technological processes.

SUBSTANCE: invention relates to metal forming and can be used in production of large diameter welded pipes. Performing step-by-step forming of sheet with bending of its edges on press forming press from the first side to impart J-shape to the section. Then the sheet is moved, installed for the second side to be bent and the second side of the sheet is bent to produce C- and O-shaped profile. Folding of sheet second side is performed at deformation mode different from first side bending deformation mode, with stroke value providing equality of radii in deformation center of first and second sides of sheet after unloading R_p2=R_p1. By changing stroke value equality of radii of front and rear ends of pipe is provided after unloading R_p3=R_pn.

EFFECT: increased quality of pipes and reduced time for equipment adjustment.

1 cl, 4 dwg, 4 tbl