This treatment consists in a warming above the critical temperature followed by a slow cooling. With this treatment we manage to increase elasticity and decrease hardness. It also eases the machining of the pieces, since it homogenizes the structure, eliminating the sharpness caused by the cold work as well as the internal tensions. We do different kinds of annealed but the regenerative, the isothermic, the globular and the subcritital are the most common ones.