Spiral Welded Pipe: It involves rolling low-carbon carbon structural steel or low-alloy structural steel strips into a billet at a specific spiral angle (known as the forming angle), and then welding the pipe seam to form the pipe. This method allows for the production of large-diameter steel pipes using narrower strips. The specifications are indicated by outer diameter * wall thickness. The welded pipes should meet the requirements for hydrostatic testing, tensile strength of the weld seam, and cold bending properties.