Shielding Gas Density Stratification
Shielding gas density stratification is the layering of different shielding gases in components. Improper densities can lead to gas flow issues and poor shielding.
Physical-Chemical Mechanism of Action
The density stratification of shielding gas results from the differing densities of shielding gas mixtures. Heavier gases such as argon are denser than air or helium, leading to layer formation. This stratification can be amplified by temperature differences or component geometries.
Metallurgical Relevance & Risks in Welding
Uneven density stratification can cause the shielding gas to flow out of the protective zone. This can lead to porosity and poorer weld quality. In extreme cases, it can cause hot cracking or component destruction.
Workshop Practice & Action Instructions
To ensure effective shielding gas density stratification, take the following steps:
• Use gas mixtures with small density differences.
• Make sure shielding gas coverage is uniform over the entire component.
• Keep the temperature in the weld zone constant and avoid strong temperature differences.