According to the production method can be divided into seamless pipe and welded pipe. Seamless steel tube manufacturing process Tube billet heating - inspection - skin - - - perforation, pickling, grinding, dry lubrication, welding head, cold drawing, solid solution treatment, pickling, pickling passivation - inspection Welding steel tube manufacturing process Strip -- inspection -- shearing -- fixed length -- qualitative -- welding -- grinding (seamless) -- fixed length -- inspection Seamless steel tube material 10#, 20#, 35#, 45#, 16Mn, 27SIMn, 20G, 40Cr, etc Welded steel tube material Q195A, Q215A, Q235A, Q345A, etc