The Process Comparison Between Cold Rolling Mills And Hot Rolling Mills

1. Processing temperature differences
Hot rolling mill: Rolling is carried out above the metal recrystallization temperature (typically 1100-1250℃ for steel parts), taking advantage of the good plasticity of metals at high temperatures.
Cold rolling mill: Rolling is carried out at room temperature and requires a lubrication and cooling system with rolling oil.
2. Differences in product features
Hot-rolled products and cold-rolled products have surface quality with oxide scale, roughness Ra3.2-12.5μm, bright surface Ra0.4-1.6μm, dimensional accuracy ±0.1-0.5mm±0.01-0.05mm, mechanical properties low strength, good ductility, strength increased by 30-50%, work hardening
3. Structural features of the equipment
Hot rolling unit
Equipped with a heating furnace and descaling device
The rolls are made of heat-resistant alloy steel
Typical configuration: roughing mill + finishing mill group
Cold rolling unit
A tension control system (20-600kN) is required.
Equipped with a rolling oil circulation system
Common types: four-roll/six-roll/twenty-roll rolling mills
4. Application fields
Hot-rolled: Construction steel bars (HRB400), medium and heavy plates (Q235), hot-rolled coils (SPHC)
Cold-rolled: Automotive sheet (DC04), tin-coated sheet (MR-T-4CA), precision instrument parts
5. Energy consumption comparison
The energy consumption of hot rolling is approximately 300-500kWh/t, while cold rolling requires multiple annealing due to work hardening, with a total energy consumption of 700-1200kWh/t