In the production, the choice of annealing and normalizing heat treatment process according to the steel grade, cold-heat processing, parts of the usability and economic.
Low carbon steel (Carbon mass fraction Wc < 0.25%), normalizing is normally used. Medium carbon steel (Wc = 0.25% ~0.5%), normalizing is normally used too. Although the medium carbon steel near the upper car content, and the hardness after normalizing is high, but the normalizing has low cost and production efficiency is high. Wc = 0.5% ~0.75%, generally using a complete annealing, reduce hardness, Improved processability. Wc≥0.75%, such as the high-carbon steel or tool steel are generally used spherical annealing as a preliminary heat treatment. If the reticular secondary cement body exists, it should be carried out by normalizing to eliminate it. Therefore, some of the carbon steel and medium carbon alloy steel is high hardness after normalizing, is not conducive to cutting, should be fully annealed. Especially, steel with more alloying elements, High temperature tempering should be used to eliminate stress, reduce hardness, improved processability.
Considering the principle of economy, because the normalizing is shorter than the annealing production cycle, the operation is simple and the process cost is low, therefore, when the steel usability and processing property meet the requirements of the conditions, the normalizing should be used as far as possible.