Annealing and normalizing of bearings

The main difference between bearing annealing and normalizing is that normalizing is a variant or special case of complete annealing. The only difference between the two is the cooling rate. Generally, annealing is carried out as the furnace cools, while normalizing is carried out in the air. Normalizing is applicable to both sub-tectoid steel and over-eutectoid copper. For eutectoid steel, normalizing is generally used to eliminate network carbides. For hypoeutectoid steel, the purpose of normalizing is basically the same as that of annealing, mainly to refine the grain size and eliminate defects in the structure. However, the pearlite sheets in the normalized structure are finer than those in the annealed one, and the amount of pearlite in hypoeutectoid steel is more than that of ferrite. Therefore, the hardness and strength of copper after normalizing are both higher than those after annealing. From this, it can be known that in production practice, Materials with network cementite in steel need to be normalized to eliminate it before other processes can be used. For materials with performance requirements after heat treatment, the annealing process should be selected according to different requirements and steel types. For example, if a certain strength and hardness are required after heat treatment, the normalizing process can be chosen. If a certain degree of plasticity is required and the strength and hardness should be reduced as much as possible, the annealing process should be selected.