The straight seam steel pipe is the steel pipe which is parallel to the longitudinal seam. Usually divided into metric welded steel pipe, welded thin-walled tube, transformer cooling tubing and so on. Straight seam welded pipe production process simple, high production efficiency, low cost, rapid development. The strength of spiral welded pipe is generally higher than that of straight seam welded pipe, it can produce welded pipe with larger pipe diameter with narrower billet, and can produce welded pipe with different pipe diameter with same width. However, the weld length increases 30~100% and the production speed is lower compared with the straight seam tube of the same length.