Spiral-welded steel pipes are seamless tubes that are formed by bending steel strips or plates into circular, square, or other shapes and then焊接 together, with visible seams on the surface. They can be classified into different types according to the welding method, such as arc-welded pipes, high-frequency or low-frequency resistance-welded pipes, gas-welded pipes, furnace-welded pipes, and Bondi pipes, etc. Based on the shape of the weld, they can be categorized as straight seam weld pipes and spiral seam weld pipes. Arc-welded pipes are used in the oil drilling and mechanical manufacturing industries. Furnace-welded pipes can be used for water and coal gas pipes, while large-diameter straight seam weld pipes are suitable for high-pressure oil and gas transportation; spiral seam weld pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. Welded steel pipes are more cost-effective and have higher production efficiency than seamless steel pipes.