The characteristics of spiral steel pipe: Longitudinal welded pipe production process is simple, high production efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the pipe with larger diameter can be produced with the narrow billet. The same width of the billet can also produce different pipe diameter. However, compared with the same length of the straight pipe, the weld length increased by 30 to 100%, and the production rate is low. Therefore, the smaller diameter of the pipe are mostly used straight seam welding, large diameter welded pipe are mostly used spiral welding