A CWB certified welder is performing a fillet weld on a structural steel component in a shop certified to CSA W47.1. The welding procedure specification (WPS) calls for a 6 mm fillet weld using FCAW-S process. After root pass completion, the welder notices porosity exceeding the limits specified in the CSA W59 standard. What is the most appropriate immediate action for the welder to take?

Question: A CWB certified welder is performing a fillet weld on a structural steel component in a shop certified to CSA W47.1. The welding procedure specification (WPS) calls for a 6 mm fillet weld using FCAW-S process. After root pass completion, the welder notices porosity exceeding the limits specified in the CSA W59 standard. What is the most appropriate immediate action for the welder to take?

Answer options:

• Continue welding, as minor porosity in the root pass is often acceptable. ✅ Grind out the defective area and re-weld it according to the WPS.
• Increase the wire feed speed to burn out the porosity.
• Switch to a different shielding gas mixture to reduce porosity.

Correct answer: Grind out the defective area and re-weld it according to the WPS.

Explanation: CSA W59 outlines acceptance criteria for welds, including limits on porosity. If porosity exceeds these limits, the defective area must be repaired, typically by grinding it out and re-welding according to the WPS. Continuing to weld would result in a non-compliant weld, and adjusting welding parameters without a revised WPS is not the immediate corrective action for existing defects.