Classification of Welded Steel Pipes

　　Welded steel pipe, also known as welded pipe, is a steel pipe made of steel plate or strip after curling and forming. Welded steel pipe has the advantages of simple production process, high production efficiency, many varieties and specifications and less equipment, but its general strength is lower than that of seamless steel pipe. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the progress of welding and inspection technology, the quality of weld seam has been continuously improved, the variety and specification of welded steel pipe has been increasing, and seamless steel pipe has been replaced in more and more fields. API 5L 14 Inch Carbon Welded Steel Pipe is divided into straight welded pipe and spiral welded pipe according to the form of weld.

　　Longitudinal welded steel pipe has the advantages of simple production process, high production efficiency, low cost and rapid development. The strength of spiral welded steel pipe is generally higher than that of straight welded steel pipe. It can produce welded pipe with bigger diameter with narrower blank, and welded steel pipe with different diameter can also be produced with blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld increases by 30-100%, and the production speed is lower.

　　Therefore, most of the smaller diameter welded steel pipes are welded by straight seam welding, while the larger diameter welded pipes are mostly welded by spiral welding.