METHOD OF MAKING HELICAL WELDED TUBES Russian patent published in 2013 - IPC B21C37/12 

FIELD: process engineering.

SUBSTANCE: proposed method comprises welding strip reels by double-sided weld seam to form the tube with making first seam on butted edges of strip on one side in lower position and, making second seam on the other side in lower position. To rule out stress raiser at intersection of the main helical seam with transverse seam is ensured by making second seam after turning the strip through 180° about its axis and, simultaneously, turning it in horizontal plane to make a loop to be locked in horizontal and vertical planes. Loop radius is defined subject to thickness, width and metal yield point. Thereafter, strip is fed into tube welding mill forming device.

EFFECT: higher quality of helical welded tubes.

1 dwg