Spiral-welded steel pipes are those formed by bending steel strips or plates into circular, square, or other shapes and then welded together, featuring a seam on the surface. They can be categorized by welding methods 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 classified by seam shape into straight seam-welded pipes and spiral seam-welded pipes. Electric-welded steel pipes are used in the oil and gas drilling industry and machinery manufacturing. Furnace-welded pipes can be used for water and coal gas pipes, while large-diameter straight seam-welded pipes are used for high-pressure oil and gas transportation. Spiral seam-welded pipes are used for oil and gas transportation, pile foundations, bridge piers, etc. Welded steel pipes are more cost-effective and have higher production efficiency compared to seamless steel pipes.