Backing Gas Purging
Shielding gas root protection prevents oxidation of the root pass using inert gases, ensuring metallurgical purity and mechanical integrity.
Physical-chemical operating principle
Inert gases like argon or helium are injected on the underside of the weld. These gases protect the root from oxygen, preventing oxidation and preserving the metallurgical purity of the material.
Metallurgical significance & welding risks
Oxidation of the root can lead to a loss of strength and toughness. This can cause cracks and wear, especially on components accessible from one side only. Shielding gas root protection prevents these problems by preserving metallurgical purity.
Workshop practice & instructions
Use inert gases like argon or helium for components accessible from one side only. Make sure the gas is routed well to the root and forms a constant protective layer. The pressure and flow conditions must be set so that oxidation is prevented throughout the entire joining process.