The annealing process of forgings can be divided into complete annealing, incomplete annealing, spheroidizing annealing, diffusion annealing (homogenizing annealing), isothermal annealing, de-stress annealing and recrystallization annealing according to the composition, requirements and purpose of annealing.
(1) complete annealing process
①Application scope: medium carbon steel, medium carbon high alloy steel castings, medium carbon low alloy steel castings, welding parts, forgings, rolled parts and other annealing treatment.
② Fully annealed B
A. Improve coarse grain structure, refine grain size, eliminate Widmannian structure and banded structure;
B. Reduce hardness and improve cutting performance;
C. Eliminate internal stress;
D. Final heat treatment for non-essential parts.

(2) Incomplete annealing process
①Application scope: annealing treatment of hypoeutectoid steel, carbon structural steel, carbon cable tool steel, low alloy structural steel, low alloy tool steel and hyeutectoid steel forgings, hot rolled parts, etc.
②Purpose of incomplete annealing: to eliminate the internal stress of forging rolling, reduce hardness and improve toughness.

(3) spheroidizing annealing
①Application scope:
A. Preparation and heat treatment of bearing and tool steels and other hypereutectoid steels;
B. Cold deformation forging annealing treatment of medium and low carbon steels and medium and low carbon alloy steels.
②The purpose of spheroidizing annealing：
A. For forgings that need to be cut, reduce hardness and improve cutting performance;
B. To improve the plasticity of cold-deformed workpiece without cutting;
C. Spherical carbide to prevent overheating of subsequent quenching and to prepare for final hot burial;
D. Eliminate internal stress.
(4) Isothermal annealing
①Application of isothermal annealing: die steel, alloy steel forgings, stamping parts.
②The advantages of isothermal annealing: it can shorten the annealing cycle and reduce the production cost.