METHOD OF A LARGE DIAMETER WELDED PIPE EXPANDING, MANUFACTURED BY BENDING FROM A SHEET AND BY LONGITUDINAL WELDING Russian patent published in 2018 - IPC B21D39/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to the metallurgical industry, namely to methods of welded pipes of large diameters manufacturing. Method provides for expansion by expansion of pipes by movement of rigid segments in radial directions. After their movement to a certain distance, they are diverted from the pipe and rotated by an angle equal to half the angle between the axes of adjacent segments, then moving the segments again in radial directions with the expansion of the pipe. Operations with the segments rotations are carried out after each loading cycle and subsequent unloading with their reciprocating rotational motion with rotations of the segments to angles equal to half the angle between the axes of adjacent segments.

EFFECT: it is also envisaged that the expansion operation with the radial movements of the segments, unloading, their subsequent rotations and repeated expansion of the pipe is carried out only at the end sections of the pipes.

3 cl, 8 dwg