What is the maximum defect size allowed per porosity, skip, or void in open butt joint?

• A. 2 mm
• B. 3 mm
• C. 1.5 mm
• D. 4 mm

Answer: (B)

In weld quality criteria, each individual defect in a weld has a size limit to ensure the joint remains strong. For an open butt joint, a single porosity, skip, or void should not exceed 3 mm in diameter. This 3 mm threshold keeps the cross‑sectional area intact enough to maintain strength while still allowing minor imperfections to be tolerated without immediate repair. If a defect were larger than 3 mm, it would fail acceptance and require grinding out and rewelding or other corrective action. Smaller defects, like 1.5 mm or 2 mm, are within the allowed range, but the key point is the maximum per defect. A 4 mm defect would not be acceptable under this criterion.