Induction Annealing is a heat treatment process which involves heating of material above its recrystallization temperature. The aim is to reach and maintain a suitable temperature for enough time followed by proper cooling. It is often used in metallurgy and material science to make the treated sample more workable by reducing its hardness and increasing its ductility (ability to undergo a change of form without breaking).
Annealing alters the physical and sometimes the chemical properties of the material as recrystallization is obtained during the process of cooling. Therefore, the outcoming structures of many alloys, including carbon steel, are both dependent on the heating and on the cooling rate. Ferrous metals, such as steel, require slow cooling to anneal. Other materials (e.g. copper, silver) can be either cooled slowly in air or quickly quenched in water.
Induction heating provides improved control of the annealing process. Repeatable heating profiles can easily be obtained by precise regulation of the heating power. Since the workpiece is directly heated by the magnetic field, a faster response can be achieved. Moreover, the high overall efficiency of the induction heating process is crucial for such lengthy treatment.
Compared to most of the standard methods, induction annealing is a clean and easy to automate, contactless approach providing a high quality of the treated workpieces.