From a processing perspective, hot rolling is a hot-working process, while cold drawing is a cold-working process. Hot rolling is performed above the recrystallization temperature, while cold rolling is performed below the recrystallization temperature.
From an appearance perspective, cold-rolled seamless steel pipes have a bright surface and a smaller diameter than hot-rolled seamless steel pipes. Hot-rolled seamless steel pipes have a larger diameter and a noticeable oxide scale or red rust on the surface.
From a precision perspective, cold-rolled seamless steel pipes have higher precision than hot-rolled seamless steel pipes and are also more expensive.
From an application perspective, hot-rolled seamless steel pipes are used in fluid transportation, mechanical structures, and other applications with less stringent dimensional requirements. Cold-rolled seamless steel pipes are used in precision instruments, hydraulic systems, pneumatic systems, and other applications with high precision requirements. The wall thickness of cold-drawn seamless steel pipes is also more uniform than that of hot-rolled seamless steel pipes.
Advantages of hot-rolled seamless steel pipes: Hot-rolling seamless steel pipes can disrupt the casting structure of steel ingots, refine the grain size of the steel, and eliminate microstructural defects, thereby making the steel structure denser and improving its mechanical properties.
Process flow of hot-rolled seamless steel pipes: Hot rolling (extruded seamless steel pipes): Round billet → heating → piercing → three-roll skew rolling, continuous rolling or extrusion → tube removal → sizing (or reduction) → cooling → billet tube → straightening → hydrostatic test (or flaw detection) → marking → warehousing.
Process flow of cold-drawn (rolled) seamless steel pipes: Round billet → heating → piercing → heading → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → billet tube → heat treatment → straightening → hydrostatic test (flaw detection) → marking → warehousing.
Post time: Mar-06-2026