Spiral Steel PipeSteel pipe with spiral seams, made from strip steel coils, which are formed by warm extrusion and焊接 using the automatic double-sided submerged arc welding process. The strip steel is fed into the pipe welding unit, passing through multiple roller rolls, gradually forming a circular billet with an open gap. The pressure of the extrusion roller is adjusted to control the weld gap between 1~3mm, ensuring that the ends of the weld are flush.