Spiral-welded steel pipes are those made by bending steel strips or plates into circular, square, or other shapes and then焊接 together, resulting in pipes with a seam on the surface. They can be classified according to the welding method into arc-welded pipes, high-frequency or low-frequency resistance-welded pipes, gas-welded pipes, furnace-welded pipes, and Bondi pipes, among others. They can also be categorized by the shape of the weld into straight seam welded pipes and spiral seam welded pipes. Arc-welded pipes are used in the petroleum drilling and machinery manufacturing industries. Furnace-welded pipes can be used for water and coal gas pipes, large-diameter straight seam welded pipes are used for high-pressure oil and gas transmission, and spiral seam welded pipes are used for oil and gas transmission, pile foundations, bridge piers, etc. Welded steel pipes are more cost-effective and have higher production efficiency compared to seamless steel pipes.