Welded steel pipes refer to steel pipes with seams on the surface that are welded by steel strips or steel plates that are bent and deformed into round or square shapes. The blanks used for welded steel pipes are steel plates or strip steels.

Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have increased. So how to classify welded steel pipes?

Welded steel pipes can be divided into arc welded pipes, high frequency or low frequency resistance welded pipes, gas welded pipes, furnace welded pipes, Bondi pipes, etc. according to different welding methods.

Welded steel pipes can be classified into straight seam welded pipes and spiral welded pipes according to the weld shape. Among them, spiral seam welded steel pipes are divided into automatic submerged arc welded steel pipes and high-frequency welded steel pipes. Welded pipes with smaller diameters are mostly straight seam welding, while large-diameter welded pipes are mostly spiral welded.

Welded steel pipes are divided into general welded pipes, galvanized welded pipes, oxygen-blowing welded pipes, wire casings, metric welded pipes, roller pipes, deep well pump pipes, automotive pipes, transformer pipes, electric welded thin-walled pipes, electric welded special-shaped pipes and spirals. Welded pipe. Generally welded pipes are used to transport low-pressure fluids. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steel that is easy to weld. Steel pipes need to be subjected to water pressure, bending, flattening and other experiments, and there are certain requirements for surface quality. Usually the delivery length is 4-10m, and fixed-length (or double-length) delivery is often required. The specifications of welded pipes are expressed by the nominal diameter (mm or inches). The nominal diameter is different from the actual. Welded pipes are divided into two types: ordinary steel pipes and thickened steel pipes according to the specified wall thickness. The steel pipes are divided into threaded and non-threaded types according to the tube end form.

Welded steel pipes are classified into round welded pipes and special-shaped (square, flat, etc.) welded pipes according to the shape of their ends.