A welding company certified to CSA W47.1 has recently started using a new type of shielding gas for their Gas Metal Arc Welding (GMAW) process. The previously qualified WPS only specified the old shielding gas. What action is required before this new shielding gas can be used on critical structural components?

Question: A welding company certified to CSA W47.1 has recently started using a new type of shielding gas for their Gas Metal Arc Welding (GMAW) process. The previously qualified WPS only specified the old shielding gas. What action is required before this new shielding gas can be used on critical structural components?

Answer options:

• No action is required, as shielding gas is a non-essential variable.
• The company must conduct a new welder qualification test with the new gas. ✅ A new Welding Procedure Specification (WPS) must be qualified with the new shielding gas.
• The welding engineer must simply approve the change without re-qualification.

Correct answer: A new Welding Procedure Specification (WPS) must be qualified with the new shielding gas.

Explanation: Under CSA W47.1 (and similar codes like ASME Section IX), a change in shielding gas composition or type for GMAW is generally considered an essential variable for the WPS. This means that if a new shielding gas is introduced, a new WPS must be created and qualified through testing to ensure that the change does not adversely affect the mechanical properties or integrity of the weld. It's not enough for an engineer to just approve it, and welder qualification is separate from WPS qualification.