The difference of normalizing VS annealing

Many friends who worked in steel industrial question me a lot of times about the difference of normalizing VS annealing.

The difference of normalizing VS annealing

Generally, normalizing is to obtain the best mechanical properties of the material, and annealing is generally to reduce the hardness of the material and facilitate machining!

The difference of normalizing VS annealing

Purpose of annealing
(1) Reduce hardness, improve machinability; (2) Eliminate residual stress, stabilize size, reduce deformation and crack tendency; (2) Refine grain, adjust structure, and eliminate organizational defects. In production, the annealing process is widely used. According to the different purposes of annealing required by the workpiece, there are various process specifications for annealing, and commonly used are complete annealing, spheroidizing annealing, and stress relief annealing.

(3) Normalizing, also known as normalization, is a metal heat treatment process in which the workpiece is heated to 30~50°C above the critical temperature, and after holding for a period of time, it is taken out of the furnace and cooled by water, spray or blowing. The purpose is to refine the grains and to homogenize the carbide distribution. The difference between normalizing and annealing is that the cooling rate of normalizing is slightly faster than that of annealing, so the normalizing structure is finer than the annealing structure, and its mechanical properties are also improved. In addition, the external cooling of the normalizing furnace does not occupy equipment, and the productivity is high. Therefore, normalizing is used as much as possible to replace annealing in production.

(4) There are various annealing processes depending on the purpose: such as isothermal annealing, homogenizing annealing, spheroidizing annealing, stress relief annealing, recrystallization annealing, stabilization annealing, magnetic field annealing and so on.

(5)Generally,which material will do normalizing or annealing?

For 1045.4140.are all able to do normalizeing,and for1.2344/H13.1.2379/d2,1.250/O1.M2,m35,/1.2080 etc. tool steel,all of them are do annealing.