Connecting steel pipe production process is simple, high production efficiency, variety of specifications, less equipment, but the general strength is lower than seamless steel pipe. Since the 1930s, with the rapid development of high quality strip rolling production and the progress of welding and inspection technology, the quality of welding seam continues to improve, the variety of welded steel pipe specifications are increasing, and in more and more fields have replaced seamless steel tubes.
Welded steel pipe is divided into straight seam welded pipe and spiral welded pipe according to the form of weld straight seam 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 welded pipe with larger diameter can be produced with a narrower blank, and the welded pipe with different diameter can also be produced with a blank of the same width. But compared with the straight seam pipe of the same length, the weld length increases by 30~100%, and the production speed is lower.
Therefore, small diameter welded pipe mostly use straight seam welding, large diameter welded pipe mostly use spiral welding.
