51 Steel Pipe Net Supply: Definition of Longitudinal Welded Pipe and Spiral Welded Pipe

Welded pipes are common pipes in gas pipelines. Welded pipes with a diameter of more than 426 mm (or 508 mm) are generally called large-diameter welded pipes. Weld pipes can be classified into spiral welded pipes and straight welded pipes according to the welding method.
Spiral welded pipe () is a low-carbon carbon steel or low-alloy structural steel strip according to a certain spiral angle (also known as forming angle) rolled into the tube blank, and then welded to make the seam, it can be used Narrow strips produce large diameter steel tubes. Spiral welded pipe is mainly spiral submerged arc welded pipe (SSAW), widely used in China for the construction of a variety of gas pipelines, its specifications with the thickness of the outer wall thickness. Spiral welded pipe with single-sided welding and double-sided welding, welded pipe should ensure that the hydrostatic test, weld tensile strength and cold bending performance to meet the requirements.
The straight seam welded pipe is a cylindrical shape in which a hot rolled coil is formed by a forming machine and deforms the steel coil into a smooth shape, and is welded by using a skin effect and a proximity effect of a high-frequency current or an arc burning under a layer of the solder. The edge is heated and melted, and it is fused under a certain squeezing force and finally cooled to form. The edge of the tube, which is melted by a high-frequency current, is called a high-frequency straight-seam welded tube (ERW), and the arc-melting one is called a LSAW (LSAW).
The main raw materials of longitudinal welded pipe are low-carbon steel hot-rolled coils and hot-rolled strips. They are widely used in petroleum, natural gas, metallurgy, construction, coal mines, ports, and machinery industries for oil and gas transportation, low-pressure water gas transmission, mineral fluid transportation, and belt type. Conveyor rollers, car transmission shafts, etc.