Welder Qualification Range and Continuity
A contractor presents a welder performance qualification for FCAW-G, 3G uphill, made on 3/8-in plate with a backing strip, dated seven months ago. The welder has since made only 1/4-in fillet welds in the flat position for about five months. The next assignment is a 1-in thick A992 CJP groove weld in the 4G overhead position without backing. The welder tells the superintendent that 3G is the hardest position, so it covers 4G, and that the 3/8-in test plate was thicker than the 1/4-in production fillets, so it qualifies 1-in groove welds. The superintendent asks you to sign the assignment. You are the welding inspector.
1. Is the welder's qualification current, and does the recent flat-position fillet work preserve continuity?
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Do not sign the assignment until the qualification is evaluated. The qualification is seven months old, so the first issue is continuity. D1.1 requires that a welder's qualification remain valid through continued welding in the process and position for which qualified, with the required documentation. Flat-position fillet welding is not the same as the 3G uphill groove qualification. The inspector should review the contractor's continuity records: dates, process, position, thickness, and joint type. If the records do not show welding in the qualified position and process within the required interval, the welder is not qualified by continuity. The fact that the welder has been working does not automatically preserve the groove qualification. The contractor must either provide acceptable continuity evidence or requalify the welder before the 4G CJP groove assignment.
2. How do position, backing, and thickness affect the range of the welder's qualification?
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Each is an essential variable in welder performance qualification. A 3G uphill test does not qualify 4G overhead; overhead is a separate position and must be tested or otherwise qualified under the D1.1 position rules. The test was made with a backing strip, and the production joint is without backing, so the backing condition must be checked against the qualification table. A welder qualified only with backing may not be qualified for a no-backing groove weld. Thickness is also controlled: a 3/8-in test coupon qualifies a limited thickness range, not unlimited thickness, and it does not qualify 1-in production merely because the test plate is thicker than some fillet welds. The inspector should use the D1.1 welder qualification table to determine the exact ranges. The superintendent's reasoning that 3G is 'hardest' and therefore covers 4G is incorrect; qualification is specific, not a hierarchy of difficulty.
3. What must happen before the welder can make the 1-in 4G CJP groove weld without backing?
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The welder must be requalified for the production conditions, or the contractor must demonstrate that an existing qualification covers them. A new performance test should use the FCAW-G process, the 4G overhead position, a groove joint without backing, and a test coupon thickness that qualifies 1-in production. The test must be inspected and tested per D1.1, including visual and bend or RT requirements as applicable. The contractor must also establish continuity for the qualified position and process. Before signing, verify the test report, the qualified thickness range, the position range, and the backing range. If the welder passes, issue the qualification record and assign the work. If not, the welder cannot make the production weld. The inspector should document the rejection of the assignment and the basis for requiring requalification.