Lsaw Steel Pipe is a single plate as raw material, steel pressed in a mold or a molding machine (roll) into a tube, using double-sided submerged arc welding and expanding the diameter. Its wide range of specifications, weld toughness, ductility, uniformity and dense better, having a large diameter, heavy wall thickness, high pressure, low temperature resistance, corrosion resistance and other advantages. In the construction of high-strength, while high-quality long-distance oil and gas pipelines, most of the required pipe is large diameter thick wall Lsaw Pipe. According to API standards, in large oil and gas pipelines, when through the alpine zone, sea, densely populated urban areas such as Class 1, Class 2 area, LSAW pipe is applicable only designated tube.