What is an Inert Gas in Welding?

An inert gas, such as helium or argon, is a gas that does not chemically combine with other elements. Such a gas serves as an effective shield of the welding arc and protects the molten weld metal against contamination from the atmosphere until it freezes.

Why is an inert gas used in welding?

When welding, an inert gas is used to displace air and create an oxygen-free environment around the weld area. This protects the molten weld from oxidation, which can cause porosity and other defects.

The most common inert gas used in welding is argon. Argon is inexpensive and provides good arc stability and penetration.
Helium can also be used, but it is more expensive and can make the arc less stable.

Inert gas welding is commonly used for welding aluminum, stainless steel, and other non-ferrous metals. It can also be used for welding ferrous metals, but this is less common because other methods, such as flux-cored arc welding, are more effective.

What is an inert gas and active gas?

An inert gas is a gas that does not chemically react with other elements.
While an active gas is one that does.

Forming gas

It is common to use a gas mixture consisting of Argon and CO2, which is often referred to as “forming gas.”

Shielding gas

The gas used to shield the weld from the atmosphere is called a “shielding gas.” The most common shielding gases are 100% Argon, CO2, or a mixture of the two.