Which welding process cannot be qualified by radiography?

Which welding process cannot be qualified by radiography?

• A. GTAW
• B. SMAW
• C. SAW
• D. GMAW (short circuit mode)

Answer: (D)

Radiography is most reliable when the weld achieved by a process has a stable, predictable geometry that clearly reveals defects such as lack of fusion, lack of penetration, porosity, or cracks. The short-circuit transfer mode of GMAW tends to produce an unstable, highly dynamic weld pool with variable penetration and a lot of transient features, which makes radiographic images difficult to interpret consistently. Because of that inconsistency, radiography is not an approved method for qualifying welding procedures when using that transfer mode. Other processes like GTAW, SMAW, and SAW generally yield welds with more predictable radiographic appearances, so radiographic qualification is appropriate for them.

Radiography is most reliable when the weld achieved by a process has a stable, predictable geometry that clearly reveals defects such as lack of fusion, lack of penetration, porosity, or cracks. The short-circuit transfer mode of GMAW tends to produce an unstable, highly dynamic weld pool with variable penetration and a lot of transient features, which makes radiographic images difficult to interpret consistently. Because of that inconsistency, radiography is not an approved method for qualifying welding procedures when using that transfer mode. Other processes like GTAW, SMAW, and SAW generally yield welds with more predictable radiographic appearances, so radiographic qualification is appropriate for them.