METHOD OF MULTI-ARC MULTI-PASS WELDING OF ELECTRIC-WELDED LARGE-DIAMETER PIPES Russian patent published in 2021 - IPC B23K31/02 B23K33/00 B23K9/18 B23K101/04 

FIELD: technological processes.

SUBSTANCE: invention relates to a method of multi-arc multi-pass welding of large-diameter electrically welded pipes. Production of pipes from DNV SAWL 485 FD steel. Edging of edges is carried out. A root suture is made, after which the internal suture is performed by multi-arc welding by four welding arcs in one pass. External seam is performed by multi-arc welding by means of four welding arcs in at least three passes. Between passes weld surface is cleaned by the slag crust. A root suture, an internal suture and at least one pass of an external suture are made in the center of the suture; the last two passages of the outer suture are made with an offset relative to the center of the suture. At that, automatic multi-arc welding under flux layer with welding wire with alloying elements is used. Articulated welding head is oriented to position when all electric arcs are lit to one common welding bath.

EFFECT: providing high mechanical characteristics during impact bending test under conditions of negative temperatures.

1 cl, 3 dwg, 2 tbl