4. Heat treatment

The characteristics and properties of castings can be modified or improved by heat treatment. According to the Association Technique de Traitement Thermique (AT T T), this is "a succession of operations – heating, holding at temperature, cooling – applied to a metal alloy in the solid state to obtain a modification of its properties". Some treatments affect the mass of the metal, others only the surface. Examples include (but are not limited to) :

• produce changes in micrographic structure;

• increase or reduce the alloy's content of certain elements by physical-chemical action (surface decarburization in the manufacture of white-core malleable cast...