Seamless steel tube is formed by cold drawing and hot rolling.


Overview of the process of two steel pipes:
1. Cold drawn (rolled) seamless steel pipe: round pipe heating piercing starting annealing pickling oil (copper) multi-pass cold drawing (cold) billet heat treatment straightening hydraulic test (inspection) marking storage.


2. Hot rolled (extruded seamless steel pipe): round pipe heating piercing rolled, rolled or extruded stripping sizing (or reducing diameter) cooling billet straightening water pressure test (or flaw detection) marking storage.