Shielding Gas

Shielding Gas according to AWS A5.32 is a type of gas used in relation to welding coverage. It is available in both gaseous and liquid storage forms, and is used for arc welding processes—whether manual, semi-automatic, automatic, machine-assisted, or robotic systems. During welding, the gas must be in a purely gaseous state (not liquid) when used for shielding purposes.

The allowable variation in gas mixtures is ±10%.

For example, in SG-AO-2, which contains 2% oxygen, the allowable deviation would be 2 × 0.1 = 0.2.

Therefore, the maximum oxygen content = 2 + 0.2 = 2.2%, and the minimum = 2 − 0.2 = 1.8%.

Examples of gas cylinder colors used in the industry (TIS 87-2537):

1. Argon (CGA 580 valve): Matte blue cylinder
2. Carbon Dioxide (CGA 320 valve): Black cylinder with white band
3. Helium (CGA 580 valve): Brown cylinder
4. Nitrogen (CGA 580 valve): Gray cylinder with black band
5. Hydrogen (CGA 350 valve): Red cylinder with black band
6. Oxygen (CGA 540 valve): Black cylinder
7. Argoshield grades 62, 63, 64 (CGA 350 valve): Matte blue cylinder with red shoulder
8. Other Argoshield grades (CGA 580 valve): Matte blue cylinder with black shoulder

On behalf of Worachart Group, we would like to express our sincere gratitude to Teacher Thares Taping for generously sharing valuable knowledge, which will be beneficial to those who wish to continue their studies in the future.