Welded steel pipe, also known as welded pipe, steel pipe with scaffolding coupler or strip after curl forming welded steel. Welded steel pipe production process is simple, high production efficiency, variety specifications, less capital equipment.

But the general strength less than seamless steel tubes. Since the 1930s, with the progress of high-quality steel rolling production as well as the rapid development of welding and inspection techniques, and continuously improve the quality of welds, welded steel pipe increasing varieties and specifications, and in more and more areas instead of no pipe joints. Welded steel pipes in the form of weld into Longitudinal and spiral welded pipe.

Welded steel pipes used in billet steel sheet or strip, its different welding process is divided into the furnace pipe, welded (ERW) pipes and automatic arc welded pipe. Because of the different forms of welded pipe is divided into two kinds of longitudinal and spiral. Its end shape is divided into circular pipe and shaped (square, flat, etc.) pipe.