Annealing Annealing, in Metallurgy and materials science, is a heat treatment that alters a material to increase its Ductility and to make it more workable. It involves heating material to above its critical temperature, maintaining a suitable temperature, and then cooling. Annealing can induce Ductility, soften material, relieve internal stresses, refine the structure by making it homogeneous, and improve cold working properties.