The blank of welded steel pipe is steel plate or strip steel. Due to different welding processes, it can be divided into steel pipe for furnace machinery (welded pipe), electric welding (resistance welding) pipe and steel pipe for automatic arc machinery (welded pipe). Because of the different welding forms, it can be divided into two types: straight seam mechanical steel pipe (welded pipe) and spiral mechanical steel pipe (welded pipe). Because of its end shape, it can be divided into round mechanical steel pipe (welded pipe) and special-shaped (square, flat, etc.) mechanical steel pipe (welded pipe).
Mechanical steel pipe (welded pipe) is divided into the following varieties due to its different materials and uses:
GB/T 3091-2008 (welded steel pipe for low pressure fluid transmission). It is mainly used for conveying water, gas, air, oil, heating hot water or steam and other general low pressure fluid and other purpose pipes. Its representative material is Q235 grade a steel.
GB/T 14291-2006 (welded steel pipe for mining fluid transportation). It is mainly used for vertical seam welded steel pipe for mine air pressure, drainage and axial gas drainage. Its representative material is Q235A and B grade steel.
GB/T 12770-2002 (stainless steel welded steel tubes for mechanical structures). Mainly used in machinery, automobile, bicycle, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00cr19ni11, 1Cr18Ni9, 0cr18ni11nb, etc.
GB/T 12771-1991 (stainless steel welded steel pipe for fluid transportation). It is mainly used for conveying low-pressure corrosive medium. The representative materials are 0Cr13, 0Cr19Ni9, 00cr19ni11, 00Cr17, 0cr18ni11nb, 0017cr17ni14mo2, etc.
In addition, welded stainless steel pipes for decoration (GB/T 18705-2002), welded stainless steel pipes for building decoration (JG/T 3030-1995), and welded steel pipes for heat exchanger (YB4103-2000).