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

In the appearance of steel pipes, the difference between seamless steel pipes and welded steel pipes is that the inner wall of the welded pipe has welding ribs, while the seamless steel pipe does not. The pressure of seamless pipes is higher. Welded pipes are generally around 10 MPa. Now welded pipe