Who knows what is the difference between double submerged arc welded pipe and longitudinal submerged arc welding?
The straight seam welding is relative to the spiral welding and the T-shaped welding, and so on.
Double submerged arc welding is also a kind of longitudinal submerged arc welding.
Double submerged arc welding should be for spot welding and single side welding, they are straight line welds, but double submerged arc welding seam is more beautiful and fine.
