Hot rolled tube is a seamless steel tube formed by plastic deformation at high temperature (usually above 1100℃). Its core characteristics and applications are as follows:
Production process principle
- Processing process
Tube billet heating: heat the solid billet to above the recrystallization temperature (＞1100℃) to eliminate casting defects and improve plasticity;
Piercing and rolling: the high-temperature billet is spun by a piercing machine to form a rough tube, then extruded by a rolling mill, and finally sized and straightened.
- Technical features
Hot rolling destroys the original grain structure of the billet, refines the organization and improves the mechanical properties (such as tensile strength and toughness);
High production speed, suitable for large-diameter thick-walled tubes (such as DN219–1420mm), but there is oxide scale on the surface and the dimensional accuracy is low.
Applications
- Energy and Chemical Industry
Oil and Gas Transportation: Casing for oil drilling, cracking unit pipeline, pressure resistance ≥15MPa;
High Temperature System: Boiler heat exchange tube (long-term temperature resistance ≤500℃), chemical reaction vessel liner.
- Heavy Structure and Transportation
Bridge main beam support, cross-sea bridge pile foundation (Q355E grade square tube bearing >2800kN);
Engineering machinery frame, ship keel structure, excellent impact resistance.
- Industrial Equipment Manufacturing
Bearing race, hydraulic cylinder, improve wear resistance through heat treatment;
Large storage tank shell, preformed parts before rolling welding.
Comparison with cold rolled tubes
| Features | Hot Rolled Pipe | Cold Rolled Pipe |
|---|---|---|
| Processing temperature | ＞1100℃(above recrystallization temperature) | Room temperature (below recrystallization temperature) |
| Surface quality | Oxide scale covered, need pickling | Bright and smooth, can be directly electroplated |
| Precision Control | Wall thickness tolerance ±0.5mm | Tolerance ≤ ±0.05mm |
| Applicable scenarios | Structural load bearing/high pressure pipeline | Precision instruments/hydraulic systems |
