In terms of welding process, the welding method of spiral welded pipe and straight seam steel pipe is the same, but the straight seam welded pipe will inevitably have many T-shaped welds, so the probability of welding defects is also greatly increased, and the welding residue at the T-shaped weld The stress is large, and the weld metal is often in a three-way stress state, which increases the possibility of cracks.
Moreover, according to the technical regulations of submerged arc welding, each weld should have an arc starting point and an arc quenching point, but each straight seam welded pipe cannot meet this condition when welding the circumferential seam, so there may be arc quenching points at the arc quenching point. More welding defects.
