METHOD AND DEVICE FOR MANUFACTURING OF PIPES WITH BUTT WELD MADE FROM METAL SHEETS Russian patent published in 2014 - IPC B21C37/06 

FIELD: metallurgy.

SUBSTANCE: metal sheet is delivered to O-forming press (1), in which it is formed at stages in a pipe (4; 104) with butt weld under impact of bending. During this process the sheet is placed on lower stamp (6) and upper stamp (9) is lifted up and down. At first a pipe with a butt weld of out-of-round blank mould (13) is formed. For this purpose at least at one stage of bending impacting inner side of metal sheet (3) correspondingly from the right or from the left of the middle determined by longitudinal axis of upper stamp (9) lowering in incrementally formed metal sheet (3), minor forming as compared to other stages of bending is performed. Then under impact of relative closing force (F) acting persistently outside on out-of-round blank mould (13) correspondingly on previously less formed sections (12a, 12b) on both sides from the middle formed is a ready pipe (104) with butt weld. The device is equipped correspondingly.

EFFECT: reducing risk of pipe deformation.

7 cl, 4 dwg