Annealing is the process of heating metal or glass and allowing it to cool slowly. This helps remove internal stresses on the metal and can strengthen it considerably. Annealing is usually performed after a hardening or cold working process, and can increase the ductility while reducing the material’s hardness.
Annealed metals are used in a variety of applications. For example, sheet metal, welded objects and metal wire often undergo annealing processes. Heavy equipment that creates a lot of heat or material displacement also may need to undergo annealing. J.F. Heat Treating, Inc. offers annealing as well as many other metallurgical services. If you’re looking to find out how annealing services in Gastonia, NC can benefit you, read on!
The Process of Annealing
Annealing can only be performed on materials which can withstand heat treatment. Cast iron, steel and certain types of copper, brass and aluminum can be annealed:
- Recovery stage: During this stage, the metal is heated in a furnace or other heating device to raise the temperature of the metal. This relieves the metal’s internal stresses.
- Recrystallization stage: In the recrystallization stage, the metal is heated to a temperature that is above the recrystallization point, but below the melting point. This allows the metal to create new grains without pre-existing stresses.
- Grain growth stage: In the grain growth stage, the metal is subjected to a slow, controlled cooling process that allows new grains to form. This process must be carefully watched in order to prevent spotting and de-crystallization. After the metal is totally cooled, it can be subjected to further processes if desired, but at this point it has increased ductility.
Annealing is not to be confused with tempering, which is a similar process. Tempering involves heating a metal to a precise temperature, and is done in vacuum or inert environments, as opposed to the careful cooling process that annealing requires.
Why Choose Annealing?
As discussed earlier, annealing increases the ductility of metal and decreases its hardness, which makes it ideal in a number of ways, including:
- Formability: If the metal you’re using is hard or brittle, you won’t be able to shape it in the way you want. Annealing allows you to bend or press that metal without a material fracture.
- Machinability: Brittle materials can cause excessive tool wear. By reducing the hardness of the material, you can also go a little easier on your tools.
- Removing residual stresses: Metal, while a sturdy material, can undergo stress fractures just like glass or wood. Annealing removes residual internal stresses and stops cracks from forming before they really start.
- And more: Annealing can also improve the appearance of the metal as well as increase its magnetic properties and electrical conductivity.
J.F. Heat Treating, Inc. is your local professional metallurgical and heat treatment company. With nearly 40 years of experience, we provide quality control and materials testing services. Call us today to discuss your metal equipment and our service options, including annealing in Gastonia, NC. We look forward to working with you soon!