<P> Annealing, in metallurgy and materials science, is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable . It involves heating a material above its recrystallization temperature, maintaining a suitable temperature, and then cooling . </P> <P> In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to a change in ductility and hardness . As the material cools it recrystallizes . For many alloys, including carbon steel, the crystal grain size and phase composition, which ultimately determine the material properties, are dependent on the heating, and cooling rate . Hot working or cold working after the annealing process alter the metal structure, so further heat treatments may be used to achieve the properties required . With knowledge of the composition and phase diagram, heat treatment can be used to adjust between harder and more brittle, to softer and more ductile . </P> <P> In the cases of copper, steel, silver, and brass, this process is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air . Copper, silver and brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal . In this fashion, the metal is softened and prepared for further work--such as shaping, stamping, or forming . </P> <P> Annealing occurs by the diffusion of atoms within a solid material, so that the material progresses towards its equilibrium state . Heat increases the rate of diffusion by providing the energy needed to break bonds . The movement of atoms has the effect of redistributing and eradicating the dislocations in metals and (to a lesser extent) in ceramics . This alteration to existing dislocations allows a metal object to deform more easily, increasing its ductility . </P>

What is the effect of full annealing compared to normalizing