annealing is to heat the workpiece to an appropriate temperature, adopt different holding time according to the material and workpiece size, and then slowly cool it, so as to make the internal structure of the metal reach or close to the equilibrium state, obtain good process performance and service performance, or make organizational preparation for further quenching. Normalizing is to heat the workpiece to a suitable temperature and then cool it in the air. The effect of normalizing is similar to that of annealing, except that the structure obtained is finer. It is often used to improve the cutting performance of materials, and sometimes used as the final heat treatment for some parts with low requirements.