Technology  >  Heat Treatment  >  Annealing
ANNEALING is a generic term denoting a treatment that consists of heating to and holding at a suitable temperature followed by cooling at an appropriate rate, primarily for the softening of metallic materials. Generally, in plain carbon steels, annealing produces a ferrite-pearlite microstructure ( Fig. 1 ). Steels may be annealed to facilitate cold working or machining, to improve mechanical or electrical properties, or to promote dimensional stability. The choice of an annealing treatment that will provide an adequate combination of such properties at minimum expense often involv es a compromise. Terms used to denote specific types of annealing applied to steels are descriptive of the method used, the equipment used, or the condition of the material after treatment.


Fig. 1 Fully annealed 1040 steel showing a ferrite-pearlite microstructure. Etched in 4% picral plus 2% nital. 5OO