METHOD OF MANUFACTURING DOUBLE-SEAM PIPES OF LARGE DIAMETER Russian patent published in 2018 - IPC B21C37/08 

FIELD: technological processes.

SUBSTANCE: invention relates to the field of production of welded steel pipes and can be used for the manufacture of double-seam pipes of large diameter. Method involves the use of two identical narrow steel sheets. First longitudinal edges of the sheets are assembled into the first joint of the edges by a first technological weld. Wide steel sheet obtained as a result of welding is formed into a tubular cylindrical billet. Second edges of narrow sheets are joined to the second joint of the edges by a second technological weld seam. On the first and second joints of the edges, the internal and external joints are applied, while the first and second technological seams are completely digested. Overlapping of internal and external working seams is not less than 1.5 mm. Expand the welded pipe. During the manufacturing process, visual inspection of process seams is performed. Before forming a tubular cylindrical blank, a wide sheet can be turned over.

EFFECT: increased homogeneity of the mechanical characteristics of the working joints of the pipe and the uniformity of the distribution of the bearing capacity between them by equalizing the number of plastic deformations for both welds.

1 cl, 11 dwg