According to different manufacturing(mfg), seamless steel pipe can be divided into hot rolled pipe, cold rolled pipe, cold drawn pipe and extruded pipe.

Hot Rolled Process for Seamless Steel Pipe

Round Pipe Billet → Heating → Punching → Three-Roller Skew Rolling, Continuous Rolling or Extruding → Pipe Detaching → 

Micro Tension Sizing or Reducing → Cooling → Straightening → Hydrostatic Test or Inspection → Marking → Warehousing

Cold Drawn Process for Seamless Steel Pipe

Round Pipe Billet → Heating → Punching → Pipe Head Treatment → Annealing → Acid Pickling → Coating Oil → Multi-pass

Cold Drawing → Pipe Billet→ Heat Treatment → Straightening →Hydrostatic Test or Inspection → Marking → Warehousing