
Spheroidizing Annealing
Spheroidize Annealing is applicable to steels which have more than 0.8% carbon. Parts are heated to between 620°C and 650°C and holding it at this temperature for a period of time to convert the micro-structure. Essentially, Cementite changes from a Lamella formation to an Alpha Ferrite matrix with particles of spheroidal Cementite (Fe3C). Spherodize annealing is generally done on parts which have been work hardened, to allow them to be further worked, either rolled in the case of coils, or drawn for wire. This resulting product has improved ductility and toughness with reduced hardness and strength. Spherodize annealing is normally carried out under a protective (endothermic) atmosphere to prevent oxidation and decarburization.