In a multi-pass groove weld, what is the purpose of passes after the root pass?

In a multi-pass groove weld, what is the purpose of passes after the root pass?

• A. To widen the root.
• B. To fill and cap the weld.
• C. To oxidize the root.
• D. To remove hydrogen from the weld.

Answer: (B)

After the root pass, the remaining passes are meant to fill the groove and cap the weld. The root pass establishes the initial fused connection between the joint faces. The filler passes deposit additional metal to completely fill the groove and restore the joint’s thickness, while the final cap pass shapes the top surface to the required profile and strength. This sequence builds up the weld in controlled layers, helps manage heat input and distortion, and yields a weld with proper cross-section and appearance. Widening the root isn’t the goal; the root is about establishing penetration, and subsequent passes fill rather than enlarge it. Oxidation is addressed primarily by shielding and process control, not by the passes themselves. Hydrogen removal isn’t a function of the passes—good shielding, material handling, and drying practices reduce hydrogen-related issues.

After the root pass, the remaining passes are meant to fill the groove and cap the weld. The root pass establishes the initial fused connection between the joint faces. The filler passes deposit additional metal to completely fill the groove and restore the joint’s thickness, while the final cap pass shapes the top surface to the required profile and strength. This sequence builds up the weld in controlled layers, helps manage heat input and distortion, and yields a weld with proper cross-section and appearance.

Widening the root isn’t the goal; the root is about establishing penetration, and subsequent passes fill rather than enlarge it. Oxidation is addressed primarily by shielding and process control, not by the passes themselves. Hydrogen removal isn’t a function of the passes—good shielding, material handling, and drying practices reduce hydrogen-related issues.