The selection of annealing methods generally have the following principles

(1) Sub-eutectic organization of various steels generally choose complete annealing, in order to shorten the annealing time, you can choose isothermal annealing;

(2) Over-eutectic steel generally choose spheroidal annealing, the requirements are not high, you can choose incomplete annealing. Tool steel, bearing steel often choose spheroidal annealing. Low-carbon steel or medium-carbon steel cold extrusion and cold heading parts sometimes also use spheroidal annealing;

(3) In order to eliminate work hardening, can choose to recrystallization annealing;

(4)In order to eliminate the internal stress caused by a variety of processes, you can choose to de-stress annealing; some high-grade high-quality alloy steel, large-scale castings, in order to improve the organizational structure and chemical composition of the unevenness, often choose diffusion annealing.