What is the difference between cold rolled steel and hot rolled steel

1. The essential difference between cold-rolled steel and hot-rolled steel:

(1) The essence of cold-rolled steel: Cold-rolled steel is steel produced by cold-rolling. Cold rolling is a steel sheet in which the steel sheet is further thinned to a target thickness at room temperature.

(2) The essence of hot-rolled steel: Hot-rolled steel is a kind of steel that is rolled above the recrystallization temperature.

2. The characteristics of cold-rolled steel and hot-rolled steel are different:

(1) Features of cold-rolled steel: The thickness of cold-rolled steel is more accurate, and the surface is smooth and beautiful. At the same time, it also has various superior mechanical properties, especially in terms of processing performance.

(2) Features of hot rolled steel: During hot rolling, the metal has high plasticity and low deformation resistance, which greatly reduces the energy consumption of metal deformation. Hot rolling can improve the processing performance of metals and alloys, that is, the coarse grains in the as-cast state are broken, the cracks are healed significantly, the casting defects are reduced or eliminated, the as-cast structure is transformed into a deformed structure, and the processing performance of the alloy is improved.

3. The processing requirements of cold-rolled steel and hot-rolled steel are different:

(1) Processing requirements of cold-rolled steel: Cold-rolled steel requires high rolling mill power and low rolling efficiency, and intermediate annealing is required to eliminate work hardening during the rolling process, so the cost is also high.

(2) Processing requirements of hot-rolled steel: hot-rolled steel is easy to roll, and the rolling efficiency is high. The hot-rolling temperature includes the opening temperature and the final rolling temperature. The determination of the opening temperature is mainly based on the solidus temperature in the alloy phase diagram. About 80%, and the final rolling temperature should be determined according to the plasticity diagram of the alloy, and it is generally required to be controlled above the recrystallization temperature of the alloy.