A heating and cooling operation implying usually a relatively slow cooling. Annealing is a comprehensive term. The purpose of such a heat treatment may be: to remove stresses; to induce softness; to alter ductility; toughness; electrical magnetic, or other physical properties; to refine the crystalline structure; to remove gases; to produce a definite micro structure.\n\n In annealing, the temperature of the operation and the rate of cooling depend upon the material being heat treated and the purpose of the treatment.