METHOD FOR MANUFACTURING A LONGITUDINALLY WELDED CLAD PIPE Russian patent published in 2022 - IPC B21C37/08 B23K31/02 B23K101/06 

FIELD: pipes.

SUBSTANCE: invention relates to the manufacture of a longitudinally welded clad pipe. The longitudinal edges of the clad steel sheet are processed simultaneously on both sides by milling. The sheets are formed into a tubular billet by the three-roll bending method and the longitudinal edges are additionally bent to a predetermined radius. Preliminary welding of the base layer is carried out by the method for single-arc automatic welding in a protective gas medium with a technological longitudinal seam along the entire length of the base layer and technological strips are welded by mechanized arc welding in a protective gas medium. The internal and external longitudinal seams of the base layer are welded by multi-arc automatic submerged arc welding. The cladding longitudinal seam is surfacing onto the inner longitudinal seam of the base layer by means of electroslag surfacing with a surfacing tape. The thickness of the deposited layer is not less than the thickness of the clad layer. The removal of technological strips is performed and the reinforcement of the outer seam is removed. The resulting pipes are expanded and trimmed.

EFFECT: increased resistance to corrosion.

9 cl, 4 dwg