A welder is qualifying for a 6G pipe welding position using FCAW-G with a specific WPS that specifies a post-weld heat treatment (PWHT). During the root pass, they encounter significant burn-through and keyholing despite adhering to the specified voltage and WFS. What is the most appropriate immediate action to take?

Question: A welder is qualifying for a 6G pipe welding position using FCAW-G with a specific WPS that specifies a post-weld heat treatment (PWHT). During the root pass, they encounter significant burn-through and keyholing despite adhering to the specified voltage and WFS. What is the most appropriate immediate action to take?

Answer options: ✅ Stop welding immediately, let the joint cool, and reassess the joint preparation and WPS

• Increase the travel speed to outrun the burn-through
• Decrease the wire feed speed while keeping voltage constant
• Switch to a smaller diameter wire to reduce heat input

Correct answer: Stop welding immediately, let the joint cool, and reassess the joint preparation and WPS

Explanation: Significant burn-through and keyholing during a root pass indicate an excessive heat input for the joint configuration or material thickness, or an incorrect root opening/land. The most appropriate immediate action is to stop welding, allow the joint to cool, and then thoroughly reassess the joint preparation and the WPS effectiveness for the specific application. Simply adjusting travel speed or WFS on the fly without understanding the root cause could lead to further defects or non-compliance.