What is the difference between a straight seam pipe and a spiral steel pipe? Straight seam steel pipe and spiral steel pipe are a kind of welded steel pipe, they are widely used in the national production and construction, straight seam steel pipe and spiral steel pipe because of different production process so there are many differences, the following specific discussion under the straight seam pipe and spiral steel pipe difference. Straight seam welded pipe production process is relatively simple, the main production process has high-frequency welding straight seam pipe and submerged arc welded straight seam pipe, straight seam pipe production efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, the main production process is submerged arc welding, the spiral steel pipe can produce different pipe diameters with the same width billet, and the welded pipe with larger pipe diameter can be produced with narrower billet. However, the weld length increases 30~100% and the production speed is lower compared with the straight seam tube of the same length. As a result, the smaller-caliber welded pipe mostly uses the straight seam welding, the large diameter welded pipe mostly uses the spiral welding. In the industry to produce large diameter straight seam steel pipe will use the tack welding technology, a short section of the straight seam will be connected to the length of the project, and the probability of the defect of the straight seam steel pipe can be improved greatly, and the welding residual stress of the T-weld is larger, and the weld metal is often in the three-direction stress state, Increases the likelihood of cracking.