The difference between hot rolled seamless steel pipe and cold drawn seamless steel pipe includes the following aspects:
- Processing: hot rolling is hot processing, cold drawing is cold processing. Hot rolling is rolled above the recrystallization temperature, cold rolling is rolled below the recrystallization temperature.
- Appearance: cold rolled seamless steel pipe surface bright, caliber size is smaller than the hot rolled seamless steel pipe. Hot-rolled seamless steel pipe caliber is more than cold-rolled seamless steel pipe, the surface has obvious oxide skin or red rust. Precision: the precision of cold rolled seamless steel pipe is higher than that of hot rolled seamless steel pipe, and the price is also higher than that of hot rolled seamless steel pipe.
- Uses: hot rolled steel pipe is used in fluid transportation, mechanical structure and other occasions that do not require high dimensions, cold rolled steel pipe is used in precision instruments, hydraulic systems, pneumatic and other demanding parts. Wall thickness of cold-drawn seamless pipe than hot-rolled seamless pipe uniform.
- Process:
Hot rolled (extruded seamless steel pipe): round billet → heating → piercing → three-roll tilting, continuous rolling or extrusion → stripping → sizing (or reduction) → cooling → billet → straightening → hydrostatic test (or flaw detection) → marking → stockpile
Cold-drawn (rolled) seamless steel pipe: round billet→heating→piercing→heading→annealing→acid cleaning→oil coating (copper plating)→multiple cold-drawn (cold-rolled)→billet pipe→heat treatment→straightening→hydraulic test (flaw detection)→marking→warehousing
