Radiography cannot be used to qualify a welder in which process/mode?

Radiography cannot be used to qualify a welder in which process/mode?

• A. SMAW process
• B. GTAW process
• C. FCAW process
• D. GMAW process with short circuit mode

Answer: (D)

Radiography isn’t reliable for welder qualification in the GMAW process when using the short-circuit transfer mode. The rapid, small-volume metal transfer and the way the root and throat are formed in short-circuit mode make it difficult for a radiograph to clearly show penetration and fusion quality to the acceptance criteria used in WPQ tests. In other words, the internal features that determine a weld’s quality in this mode can be obscured or ambiguous on film, so radiography cannot be used to certify a welder’s qualification for this specific process/mode. For other welding processes or modes, radiography can provide the needed visibility to assess flaws and meet the qualification criteria.

Radiography isn’t reliable for welder qualification in the GMAW process when using the short-circuit transfer mode. The rapid, small-volume metal transfer and the way the root and throat are formed in short-circuit mode make it difficult for a radiograph to clearly show penetration and fusion quality to the acceptance criteria used in WPQ tests. In other words, the internal features that determine a weld’s quality in this mode can be obscured or ambiguous on film, so radiography cannot be used to certify a welder’s qualification for this specific process/mode. For other welding processes or modes, radiography can provide the needed visibility to assess flaws and meet the qualification criteria.