What is the purpose of visual inspection (VT) in GTAW quality control, and what would constitute a defect?

• A. Determine filler metal cost and supplier.
• B. Verify weld geometry and finish; defects include porosity, cracks, lack of fusion, excessive undercut.
• C. Confirm the color of shielding gas.
• D. Assess welds by mechanical testing only.

Answer: (B)

Visual inspection in GTAW quality control focuses on the visible aspects of the weld to ensure the surface quality and geometry meet requirements. It checks how the bead looks, its contour and finish, and that the weld aligns with the joint design, including the crown, toe, and overall dimensions. A defect shown by VT would be surface flaws such as porosity (small holes or rough surface from trapped gas), cracks (fissures in the weld or heat-affected zone), lack of fusion (the weld not fusing properly with the base metal), or excessive undercut (a groove at the weld toe that removes base metal and weakens the weld). VT is about what can be seen on the surface and the weld’s form, not about filler metal cost, shielding gas color, or mechanical properties assessed by testing.