Thick-walled square pipes are widely used in foreign construction industry. They are used as roof trusses, purlins, trusses, rigid frames, wall frames, keels, roof panels, wall panels, floors, doors and windows, and even containers, pipes, cofferdams, steel sheet piles, Breakwaters, etc. In recent y

With the continuous development of oil and gas pipelines to large diameters and high pressures, spiral submerged arc welded steel pipes also continue to develop to large diameters, large wall thicknesses and high steel grades. The double wire submerged arc welding process is playing more and more in