Inductive annealing is a heat treatment where a material is exposed to a high temperature for a long time and then slowly cooled down. Heat treatments by inductive annealing are characterized to a large extent by induced microstructural changes that are ultimately responsible for changing the mechanical properties of the material. The purpose of inductive annealing is to reduce the hardness of the metal and to improve the toughness.
Inductive annealing specifically relates to the process whereby a material is brought to its softest possible point. An annealing process softens the metal but not to the fullest extent possible.
The degree of annealing depends on the material, the maximum temperature reached, and the duration of the cool down time. The process of inductive annealing to relieve internal stress is used to reverse the effects of cold work; that is, to soften and improve the toughness of a metal previously cured by cold-hammering. Internal stresses can arise as a result of plastic deformation processes such as grinding or cutting, uneven cooling in a welding or casting process or a transformation phase. Deformation and warping can occur if internal stresses are not removed. Inductive annealing eliminates these stresses when the workpiece is heated to the recommended temperature, is maintained there long enough and is slowly cooled to room temperature.