lsaw-Longitudinally Submerged Arc Welding (longitudinally Submerged Arc Welding, abbreviated as LSAW). Longitudinal submerged arc welded pipe (LSAW) is produced by using a single medium and thick plate as the raw material, pressing (rolling) the steel plate in a mold or forming machine into a tube blank, using double-sided submerged arc welding and expanding the diameter. The finished product has a wide range of specifications, and the weld has good toughness, plasticity, uniformity and compactness. It has the advantages of large pipe diameter, pipe wall thickness, high pressure resistance, low temperature resistance and strong corrosion resistance.
When constructing high-strength, high-toughness, and high-quality long-distance oil and gas pipelines, most of the steel pipes required are large-diameter thick-wall LSAW pipes. According to API standards, in large-scale oil and gas transportation pipelines, when passing through Class 1 and Class 2 areas such as alpine areas, seabeds, and densely populated cities, LSAW pipes are the only designated applicable pipe type. According to different molding methods, it can be divided into:
UOE welded pipe: After the single steel plate is pre-bent at the edge, it undergoes U forming, O forming, internal welding, external welding, mechanical cold expansion and other processes;
JCOE welded pipe: Pre-welding, forming, and cold expanding after welding according to "J-C-O-E";
HME welded pipe: It is formed by mandrel rolling method according to "C-C-O", and after welding, it is cold-expanded.
