Definition: Annealing is a thermal process used to bring a metal closer to its equilibrium state. In this soft state, the uniform microstructure will allow for excellent ductility and workability. In order to perform a full anneal in ferrous metals, the material must be heated above its upper critical temperature long enough to fully transform the microstructure to austenite. The metal must then be slow-cooled, usually by allowing it to cool in the furnace, to allow maximum ferrite and pearlite phase transformation. Other metals such as brass, silver and copper may be fully annealed by the same process, but may be quickly cooled, even water quenched, to finish the cycle.