Annealing, code as Th, is to heat the steel parts above Ac1 or Ac3 (30~50℃), keep them warm for a period of time, and then cool them slowly (usually furnace cooling).

 Normalizing, code  as Z, is to heat the steel to above Ac3 or Acm (30~50℃), keep it warm for a period of time, and then cool it in the air, the cooling speed is slightly faster than annealing.

The main difference between bearing annealing and normalizing 

 Normalizing is a metamorphosis or special case of complete annealing, the two of them are only different in cooling rate. Annealing is cooling with the furnace.

 Usually, normalizing is cooling in air and  suitable for both Hypoeutectic steel and hypereutectoid steel. For eutectoid steel, normalizing is generally used to eliminate network carbides. For hypoeutectoid steel, the two have same purpose, mainly to refine the grain and eliminate the defects in the structure. 

The pearlite sheet in the normalized structure is finer than the annealed, and the amount of pearlite in the hypoeutectoid steel is more than the amount of ferrite. Therefore, the hardness and strength of the steel after normalizing are higher than that of the annealed It can be seen that in the production practice, materials with mesh cementite in steel need to be eliminated by normalizing before other processes can be used, and materials with performance requirements after heat treatment, according to different requirements and steel types Different choices of annealing process, such as: require certain strength and hardness after heat treatment, can choose normalizing process; require certain plasticity, should choose annealing process to reduce strength and hardness as much as possible.