Purging

From GAWDAwiki

Purging is a procedure in which a gas or liquid is forced into a component to remove contaminants from the system.^[1]

During the welding of chrome nickel steel, oxidation occurs in the weld seam if oxygen reaches this area unhindered. The resulting oxidized surfaces are no longer corrosion resistant and further treatment is necessary. Usually an inert gas such as argon, which is heavier than air, is used. Other purging gases can be nitrogen and nitrogen/hydrogen blends.^[2]

References

1. http://www.bocindustrial.co.uk/bocindustrial/technical/glossary/a.asp
2. A.J. Schenk