Spiral-welded steel pipes are those formed by bending and shaping steel strips or plates into circular, square, or other shapes and then焊接 together, resulting in a seamless surface. They are 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. According to the shape of the weld seam, they can be classified as straight seam welded pipes and spiral seam welded pipes. Arc-welded 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 transmission. Spiral seam welded pipes are used for oil and gas transmission, pipe piles, pier piers, and more. Welded steel pipes are more cost-effective and have higher production efficiency compared to seamless steel pipes.