Atomic Hydrogen Welding (AHW)

Definition - What does Atomic Hydrogen Welding (AHW) mean?

Atomic hydrogen welding (AHW) is an arc welding process that makes use of an arc between two tungsten metal electrodes within an atmosphere composed of hydrogen. The process was invented by Irving Langmuir in his studies about experiments about atomic hydrogen.

The electric arc produced in the process efficiently breaks up the molecules of hydrogen that later recombine through an extreme release of heat. The heat that is produced by the torch in the process of AHW is enough to weld tungsten, which is a highly refractory metal.

Corrosionpedia explains Atomic Hydrogen Welding (AHW)

The existence of hydrogen in the shielding atmosphere in atomic hydrogen welding acts as the protection or barrier of metals against contamination by oxygen, nitrogen and carbon, which can severely damage the properties of various metals.

In this type of welding process, the work pieces are combined through heat that is obtained from hydrogen stream passing through the electric arc between two electrodes made of tungsten. The welding arc produces the energy, so that a chemical reaction takes place where heat is obtained to initiate the welding process.

The equipment is composed of a torch along with electrodes made from tungsten adjusted and inclined to make the arc more stable. The annular nozzles that surround the electrodes hold the hydrogen coming from the cylinders containing gas. During the process, work pieces are thoroughly cleaned in order to eliminate dirt, impurities and oxides in order to achieve a perfect weld.

The arc brings the tungsten electrodes together and then undergoes immediate separation by a tiny distance so that the arc is sustained between the electrodes. This welding process is faster than others and is capable of preventing oxidation through the hydrogen envelope, reducing the need for a shielding gas or separate flux.

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