Annealing is a heat treatment process used for metal and glass to change their properties. Glass is kept at a high temperature to remove any stresses and then slowly cooled to seal in strength and durability. Metal is also introduced to high temperatures before being slowly cooled to seal in ductility and strength. The temperature and time required for annealing glass and metal depend on the type of material. In genetics, annealing refers to the process of DNA and RNA pairing to form a double-stranded polynucleotide.
Annealing is the process by which both metal and glass are heat treated to change their properties. If the process is applied to glass, it is kept at a high temperature to free the object from any stresses it has undergone in the manufacturing process. Once the glass has been subjected to a consistently high temperature for the required amount of time, it is then slowly cooled which acts to seal in the piece’s strength and durability. As with the glass annealing process, when the metal is annealed it is first introduced to a very high temperature before being cooled to seal in the ductility and strength of the metal.
The process of subjecting glass to a constant temperature is called “soaking.” The higher the temperature the glass is immersed at, the shorter the length of time the glass needs to be exposed to that temperature. Naturally, glass exposed to very high temperatures takes longer to cool down. Care should be taken not to expose the glass to a temperature which can adversely affect the structure of the glass. Conversely, when glass is annealed at lower temperatures, it requires longer soaking times but proportionately less cooling times. The type of soaking a glass needs to undergo depends on the type of glass. General guidelines suggest that Bullseye, Lausha, and Effetre eyewear should undergo an annealing temperature of approximately 940ºF (504ºC); Satake glass about 890ºF (476ºC); and borosilicate glass at approximately 1050ºF (566ºC).
Annealing of metal is a similar process to that of glass. For a full annealing of the metal, it must be introduced at an approximate temperature of approximately 90ºF (50ºC) above the austenitic temperature. This temperature must be maintained for a period such as to ensure that all of the material involved is transformed into Austenite or Austenite-Cementite. Upon completion of this process, the metal is slowly cooled to approximately 36ºF/hr (20ºC/hr) in a furnace at approximately 90ºF (50ºC) in the Ferrite-Cementite range. Once this temperature is reached, the metal can then complete the annealing process by cooling to normal room temperature.
The term annealing is also used in another context. In the science of genetics it refers to the process in which DNA and RNA pair by hydrogen bonding to a sequence that is complementary to their own to form a double-stranded polynucleotide.
Protect your devices with Threat Protection by NordVPN
