Induction annealing enables precise and reliable control of metal material properties. Induction annealing is mainly used for soft and stress-relief annealing, offering enormous advantages over conventional methods. Induction annealing enables thermal removal of impurities during bright annealing. Induction annealing is mainly used in soft annealing and stress-relief annealing and offers enormous advantages over conventional methods.
Induction annealing enables the thermal elimination of impurities in the material during bright annealing.
Induction annealing is a sub-area of induction heating. The aim of induction annealing is to specifically influence metals with regard to hardness, toughness and internal stresses, in order to attain optimal material properties. The advantage of induction annealing is mainly the targeted and reproducible heating of workpieces in order to always ensure the same results. As induction annealing generates heat directly in the workpiece by means of an alternating electromagnetic field, this process can be controlled very precisely and also has a very high degree of efficiency due to its effective use of energy. This ensures a homogeneous heat distribution and an even depth of penetration in the workpiece. With induction annealing, cooling is not carried out abruptly with water or coolants as in induction hardening. Instead, the temperature of the workpiece is reduced slowly. The entire heating process is carried out without contact and in a very short time.
Induction annealing offers excellent options for heat control, as the entire process can be optimally fine-tuned to achieve the desired material properties via the frequency, power and (see Brazing) annealing time. This guarantees a high quality of heat treatment and ensures reproducibility, an especially important aspect of mass production.
Induction annealing is used when the degree of hardness of metal is to be reduced, in order to subsequently transfer the workpiece for instance to a forming process. This procedure is also referred to as soft annealing, as the strength of the metal is reduced and the toughness is increased significantly. This enables metals treated by soft annealing to be much better deformed. The temperature range for soft annealing may vary significantly depending on requirements and the specific application.
Another variant of induction annealing is stress-relief annealing. Much lower temperatures are used in stress-relief annealing. Metal workpieces are heat-treated in this induction annealing process in order to minimize stresses created during machining or forming, and in the best-case scenario to eliminate them completely. Stress-relief annealing is also used for the heat treatment of workpieces with high internal stresses.