An annealing furnace is a type of heat treatment furnace primarily used for annealing large-scale carbon steel and alloy steel parts. Annealing is a heat treatment process that involves heating the metal material to an appropriate temperature, maintaining it for a certain period, and then cooling it slowly.
Common annealing processes include recrystallization annealing, stress-relief annealing, spheroidizing annealing, and full annealing. The main purposes of annealing are to reduce the hardness of the metal material, improve plasticity for easier cutting or pressure processing, decrease residual stresses, enhance the homogenization of structure and composition, or prepare the structure for subsequent heat treatment. Annealing furnaces are classified by heat source, mainly including electric furnaces, coal-fired annealing furnaces, oil-fired annealing furnaces, natural gas annealing furnaces, and gas annealing furnaces. Additionally, bell-jar bright annealing furnaces are a type of annealing furnace widely used for bright annealing of non-ferrous metals such as copper and aluminum alloys, as well as ferrous metals including plain carbon steel, silicon steel, and alloy steel in the form of coils, pipes, and wires.