What is the typical sequence for a multi-pass GTAW weld on a butt joint (root, fill, cap) and the purpose of each pass?

• A. Root pass shapes final contour; fill passes remove defects; cap pass establishes penetration.
• B. Root pass establishes fusion and penetration; fill passes build the weld bead to the required height; cap pass shapes the final contour and smooths the surface.
• C. Root pass only; fill and cap are optional.
• D. Root pass is for decoration only.

Answer: (B)