Welded steel pipe is divided into straight seam welded pipe and spiral welded pipe according to the form of weld.
Classification by production method: Process classification - arc welded pipe, resistance welded pipe, (high frequency, low frequency)
gas welded pipe, furnace welded pipe.
According to different materials and uses, it is divided into welding steel pipes for mining fluid transportation, galvanized welded steel 
pipes for low pressure fluid transportation, and electric welded steel pipes for belt conveyor rollers.