Welded steel pipes refer to steel pipes with seams on the surface that are welded after bending and deforming steel strips or steel plates into round or square shapes. The billet used for welded steel pipe is steel plate or strip steel.

According to different welding methods, it can be divided into arc welded pipe, high frequency or low frequency resistance welded pipe, gas welded pipe, furnace welded pipe, Bondi pipe and so on.

Electric welded steel pipe: used in oil drilling and machinery manufacturing. Furnace welded pipe: can be used as water gas pipe, etc., large diameter longitudinally welded pipe is used for high pressure oil and gas transportation, etc.; spiral welded pipe is used for oil and gas transportation, pipe piles, bridge piers, etc.