A 6G Pipe Test Offered as Cover for a Small-Bore GTAW Joint
A fabricator's welder performance records show one welder tested in August 2023 on 8.625 in OD × 11.1 mm wall pipe in the 6G position: GTAW root and hot pass with ER80S-B2 (F-6), SMAW fill and cap with E8018-B2 (F-4), P-No. 4 base metal, consumable insert open root, all test specimens passing bend. In March 2024 the same welder is assigned to a 2.375 in OD × 5.5 mm wall P-No. 1 pipe, welded entirely by GTAW with ER70S-2 in the rolled position with an open root. The welder has run no GTAW since the October 2023 shutdown but has run SMAW almost weekly since then. The shop superintendent argues the 6G test was the hardest position and therefore 'covers everything on site', and wants the joint started on the next shift.
1. May the welder be released to this joint today? Work through each qualification variable and state your conclusion.
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Not yet - release the welder only after requalification. Working through the variables:
- Diameter. The test was on 8.625 in OD pipe. Under ASME IX Table QW-452.3, a performance test on pipe of 2.875 in OD or larger qualifies only pipe of 2.875 in OD and larger. The 2.375 in production joint is outside that range, so the existing qualification does not reach it.
- Thickness. An 11.1 mm coupon qualifies a 5.5 mm production thickness under the 2t rule of QW-452.1(b). Thickness is not the problem.
- F-number and filler. ER70S-2 is F-6, matching the F-6 GTAW filler used in the test; no F-4 welding is proposed. The filler metal variable is satisfied.
- Base metal. The test was P-No. 4; production is P-No. 1. Treat the extension as unproven and qualify on the production P-number rather than arguing the point on the floor.
- Continuity. GTAW has not been used since October 2023. Under QW-322.1 a welder who has not welded with a process for six months loses qualification for that process. This alone blocks the release, irrespective of diameter.
The superintendent's 'hardest position' argument is only about position. Position is one essential variable among several, and it cannot cure a diameter or a continuity failure.
2. Set out the requalification test you would require, and the records you would demand before the welder starts work.
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Test the welder under the conditions closest to production, but on a coupon no larger than necessary so the qualified range covers small bore:
- Coupon: 2.375 in OD pipe (or 2 in OD if the shop has it), wall thickness at least equal to the 5.5 mm production wall, P-No. 1, open root, no backing, ER70S-2, GTAW all passes.
- Position: 6G so the qualification covers all positions; confirm from the applicable row of QW-452.3 that the diameter range obtained reaches the production size - a test below 2.875 in OD qualifies pipe of 1 in OD and above.
- Examination: visual plus the bend specimens required by QW-452 and QW-462; record whether any specimen exceeded the acceptance limits of QW-191.
- Records: a WPQ signed by the test supervisor and the responsible inspector, listing every essential and, if impacts apply, supplementary essential variable - process, P-number, F-number, filler classification, diameter, thickness, position, progression, backing, and the test date.
- Continuity control: log the welder in the register with the six-month expiry date for each process separately, and show the production supervisor the date.
I would also ask why the 2.375 in work was planned against a qualification register that the QA function should have screened. That is an administrative failure, not a welder failure.
3. The superintendent accepts the requalification but refuses to log separate continuity per process, saying 'a welder is a welder'. How do you handle this, and what is at stake?
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Continuity is traced per welder per process, because qualification is granted per process. A welder who has run SMAW continuously but has not struck an arc with GTAW for eight months has demonstrated nothing about manual dexterity for a thin-wall open root, and the code treats that as a lapse. A single combined entry in the register would conceal exactly the failure this case illustrates.
Handling: state the requirement in writing, quote QW-322.1 in the response, and show the consequence - if a joint is made by a lapsed welder, the weld is unqualified, and the disposition is not a paperwork fix but possible excavation and rewelding, plus a nonconformance against the quality programme. Offer the practical alternative: a short, cheap requalification test whenever a process is about to lapse, which is far cheaper than a cut-out on a finished line.
At stake is traceability. If a future audit or failure investigation cannot show which process the welder was current in on the day of welding, every joint that welder touched becomes suspect. Escalate to the QA manager if the refusal persists, and record the escalation.