METHOD FOR MANUFACTURING LONGITUDINALLY ELECTRIC-WELDED PIPE OF LARGE DIAMETER Russian patent published in 2023 - IPC B21C37/08 B23K9/18 B23K101/06 

FIELD: production of large diameter welded pipes.

SUBSTANCE: method for manufacturing a longitudinally electric-welded pipe of large diameter includes preparing and forming a pipe billet, welding, calibrating and cooling the pipe. As a pipe billet, hot-rolled or sheet products are used, which are prepared by centering them in a recoiling reel and arranging them on a butt-welding table, on which the rolled metal is fed with an end part for joining pre-cut transverse parts and their submerged arc welding. The forming of the pipe billet is in several stages using a flattening machine, which reduces the waviness and warp of rolled metal, using forming stands to form the required configuration of the pipe billet, and using seam guides for additional physical impact for consistent final shaping. The internal longitudinal seam welding is carried out by submerged arc welding in one pass, plasma cutting of the pipe to a given length, removal of flux residues and slag crust, welding of process plates to the front end of the pipe in order to adjust the welding equipment, the external longitudinal seam welding by submerged arc welding and subsequent removal of process plates.

EFFECT: development of the pipe production method, including pipes of large diameter (325-720 mm), with high efficiency and speed of technological processes, as well as the possibility of obtaining pipe products that are variable in terms of the material used, which does not allow increased stress and cracks in its walls.

1 cl, 1 dwg