Spiral-welded steel pipes are those formed by bending and shaping steel strips or plates into circular, square, and other shapes, then welded together, resulting in pipes with seams on the surface. They can be classified 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. According to the shape of the weld seam, they can be divided into straight seam welded pipes and spiral seam welded pipes. Electric welding pipes are used in the petroleum drilling and mechanical manufacturing industries, among others. Furnace-welded pipes can be used for water and coal gas pipelines, and 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, and more. Welded steel pipes are less costly and more efficient in production than seamless steel pipes.