Achievement of the most complete pearlite matrix possible (see Structure formation of cast iron) in cast iron alloys and steel through heat treatment. In cast iron, pearlitization is practically equivalent to normal annealing.
The annealing temperature for cast iron is between around 850 and 950°C, i.e. above the critical temperature and therefore eutecticcarbide, if present, is also made to decompose.
At the said annealing temperature, a complete austenitic structure is obtained (see Austenitic cast iron). The cooling after annealing is done in air which is moved intensely (forced air) in order to prevent ferritization around the graphite diffusions (ferrite borders); on the other hand the cooling must not be too abrupt so that no martensite forms (s. a. Heat treatment).
Pearlitic influence factor
Structure formation of cast iron