Annealing is a metal science. Without it, many of things that that we uses and take for granted in our every days, wouldn’t exist. Though the process is not a common language terms, it is well known and used every day in industries like metal forming, automotive, and others.

The process of annealing is to help metals such as steel, cast iron, aluminum, copper, and brass become more ductile so that the metals can be formed into various shapes.  The processes of drawing metal require those materials to be ductile (a materials amenability to be shaped and formed) so that it allows the product to engineered to particular shapes and specifications. The process is used to reduce damage to the shaping tool or the metals being shaped. It can also improve the machinability and make metals less brittle in the forming process.

The Process

Annealing is typically done in large ovens at very high temperatures, usually at range between 500F (260C) and 1400F (760C). Those temperatures depend on the metal alloy going through the process. This raises the temperature in the metal so the internal stresses are relieved which is known as Recovery. In the Recrystallization stage, material is heated above this stage of temperature, yet below melting temperatures. New grains form without any pre-existing stresses that were there to reappear. Lastly, in Gain Growth stages, the new grains can fully develop. Because the material is allowed to cool at a pre-determined rate, ductility is achieved in the material so it can be shaped.

What Gases Make It Happen

There are particular gases that are specialized for the process of annealing. 

Nitrogen

Nitrogen is an inert gas that is great for annealing non-ferrous metals, alloy steels, and performing decarburization.

Argon

This gas is also used for annealing non-ferrous metals, stainless steel, and some other alloy steels.

Hydrogen

Hydrogen is known to reduce iron oxide to iron and can decarburize steel.  It is also known to enhance heat transfer and can react with oxygen that may be present. It is used in bright annealing, stainless steel, non-ferrous metals, low carbon steels, and electrical steels.

Endothermic Gas

If you are looking to reduce the amount of scale on the metal surface, then an Endothermic Gas mixture is the right product for your needs. A special blend of Carbon Monoxide gas, Hydrogen gas, and Nitrogen gas would be a great selection for such use.

Annealing is also done in forming gas, a mixture of hydrogen and nitrogen.

nexAir has a full array of gas that are and can be designed for any  of your specific annealing applications. Contact your gas specialist today and lean on our KnowHowTM to get your job done right.