What is Backing Gas in Welding?

Backing gas is a shielding gas used on the underside of a weld bead to protect it from atmospheric contamination. It is often used in welding processes such as gas tungsten arc welding (GTAW) and plasma arc welding (PAW).

What gases are used as backing gases?

The most common backing gases used in welding are:

argon,
helium,
carbon dioxide,
oxygen.

These gases are widely available and can be easily mixed to create the desired atmosphere for each welding application.

What is purge gas in welding?

The purge gas is a gas used to protect the weld pool from atmospheric contamination. It is often used in welding processes such as GTAW and PAW.

Purge gas can be either inert or active. Inert gases, such as argon and helium, create a protective atmosphere that prevents oxidation and other reactions at the weld pool.

What is trailing gas in GTAW?

Trailing gas is a shielding gas used to protect the molten weld pool from atmospheric contamination. It is often used in welding processes such as GTAW and PAW.

Conclusion

Backing gas is an important part of the welding process and can help to improve the quality of the weld. It is important to select the appropriate backing gas for each welding application to ensure the best possible results.