Annealing and the Importance of Gas

Annealing is a metal science. Without it, many of the things that we use and take for granted every day wouldn’t exist. Though the process is not a common language term, 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 process of drawing metal requires those materials to be ductile (a materials amenability to be shaped and formed) so that it allows the product to be engineered to particular shapes and specifications. The process is used to reduce damage to the shaping tool and 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 a rage between 500◦F (260◦C) and 1400◦F (760◦C). The temperature is dependent upon which stage of the process the metal alloy is going through. The Recovery stage, which happens at the lower end of the temperature range, is when the metal is heated so that the internal stresses are relieved. In the Recrystallization stage, material is heated above its recrystallization temperature but below its melting temperature. This stage allows for new grains to form without any pre-existing stresses. Lastly, in the Grain Growth stage the material is cooled at a specific rate allowing new grains to develop.

What Gases Make It Happen

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


Nitrogen (N2)
Nitrogen is an inert gas that is great for annealing non-ferrous metals, alloy steels, and performing decarburization.


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


Hydrogen (H2)
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.

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