What is the function of tack welds in GMAW and how are they removed after final welding?

• A. Tack welds serve as final structural welds and are left in place.
• B. They are cosmetic; removed with a wire brush.
• C. Tack welds do not influence alignment; removed only by grinding.
• D. Tack welds hold joints in alignment during welding; remove after welding with grinder or cutouts or leave in place if specified by design.

Answer: (D)

Tack welds in GMAW are small, temporary welds that hold the pieces in proper alignment and spacing so the joint maintains correct fit-up while the main welds are made. They prevent movement and distortion as the parts heat and cool, but they aren’t meant to provide the final structural strength. After the final weld is completed, tack welds are removed to avoid affecting surface finish or causing defects in the completed joint. They’re usually ground flush with the base metal or cut out if needed, though the design may specify leaving them in place in some cases.