Below is a list of Annealing manufacturers from LONDONDERRY, New Hampshire. Annealing is a heat treating process that is commonly used in a number of industrial and commercial settings to heat and slowly cool a number of materials in order to alter their physical properties for improved strength and ductility. This particular type of heat treatment is exceedingly common. Though most often used to relieve the internal stresses of glasses and metals, ceramic annealing is also available.