The main differences between hot rolling and cold rolling are processing methods, mechanical properties, surface quality and application areas.

Processing method

Hot rolling: Hot rolling is the rolling process performed above the recrystallization temperature. Usually, the steel ingot or billet is heated to 1100-1250℃ before rolling. During the hot rolling process, the metal has high plasticity and low deformation resistance, which can significantly reduce the energy consumption of metal deformation. ‌

Cold rolling: Cold rolling is carried out at room temperature, using hot-rolled steel coils as raw materials. After pickling to remove the oxide scale, cold rolling is carried out. During the cold rolling process, the steel will undergo continuous cold deformation, causing cold work hardening, which will increase the strength and hardness, but reduce the toughness and plasticity indicators. ‌

Mechanical properties and surface quality

‌Hot-rolled‌: Although the strength of hot-rolled steel is not very high, it is sufficient to meet general needs. During the hot rolling process, the processing properties of metals and alloys are improved and casting defects are reduced, but the surface quality is relatively poor and the thickness size control accuracy is low.

‌Cold rolling‌: The thickness of cold-rolled steel is more precise, the surface is smooth and beautiful, and the mechanical properties are superior, especially in terms of processing performance. The surface quality, appearance and dimensional accuracy of cold-rolled steel plates are better than those of hot-rolled plates, but residual stress will also be generated during the cold rolling process.

Application Areas

Hot-rolled steel is widely used in construction, bridges, ships, vehicle production and other fields. Due to its excellent plasticity and toughness, it is often used to manufacture structural parts and mechanical parts. ‌

‌Cold rolling‌: Cold rolled steel is mainly used for prod