Seamless steel tubes are formed by cold drawing and hot rolling.
A summary of two kinds of steel pipe technology:
1, cold drawn (rolling) seamless steel pipe: round pipe, heating, perforation, start up, annealing, acid washing, oil (copper), multi pass cold pull (cold), billet, heat treatment, straightening, water pressure test examination, marking and storage.
2, hot rolling (extrusion seamless steel pipe): round pipe, heating, perforation, roll, rolling or extrusion, off tube, sizing (or shrinkage), cooling, billet to straightening, water pressure test (or defect detection), marking, storage.
