Do tack welders need to be qualified under AWS D1.1?

If the tack weld is incorporated into the final weld, yes — the tack welder must be qualified under the applicable WPS. If the tack weld is completely removed before final welding, qualification requirements are less strict, though the welder should be competent in the process.

Does preheat apply to tack welds?

Yes. AWS D1.1 requires the same preheat for tack welds as for production welds with the same base metal, thickness, and process. Tacking without preheat on thick or restrained joints is a common source of hydrogen-assisted cracking.

Can I use a prequalified WPS for tack welding?

Yes, if the tack weld parameters fall within the prequalified envelope. The WPS used for tacking should be specified in the procedure documents — either the same WPS as the production pass or a separate tack-weld WPS. Either way, a documented WPS should cover the tack.

Who is responsible for specifying tack weld requirements on the WPS?

The CWI or QC manager who approves the WPS. The Annex M WPS form's pass schedule and notes sections should document tack weld parameters when tacks will be incorporated. Leaving tacking parameters unspecified is a common gap that auditors flag.

Tack weld WPS requirements under AWS D1.1

AWS D1.1 treats incorporated tack welds the same as production welds: qualified welder, WPS, preheat. Here's what shops get wrong and what the code requires.

Tack welding is the most informal operation in most fab shops. Parts get fitted, a tacker runs a bead or two to hold the joint, and the job moves to the qualified welder for the production pass. At many shops, that tacker is a fitter, an apprentice, or whoever is nearby — not necessarily a qualified welder under the applicable WPS.

AWS D1.1 does not share the informal attitude toward tacking. Whether tacks require a WPS and a qualified welder depends on one critical factor: whether the tack weld is incorporated into the final weld.

Incorporated vs. removed tacks

Incorporated tack welds — meaning they become part of the final weld, either fused into the root pass or left within the body of a fillet — must be made by a qualified welder following a WPS. The reasoning is direct: the tack is now structural material inside the finished joint. Any defect in the tack (cracking, porosity, lack of fusion at the tack ends) becomes a defect in the finished weld.

Removed tack welds — made to hold the joint for fit-up and then completely excavated before final welding — are held to a lower standard. The welder doesn't need a WPS qualification for the tacking process alone, though they should be competent in the process and producing sound weld metal.

Most production fillet welds and groove welds use incorporated tacks. That means the informal, anyone-can-do-it attitude toward tacking is in conflict with the code for most structural fabrication work.

Rule library based on AWS D1.1:2025; verify against your governing edition.

Preheat on tack welds

Preheat requirements apply to tack welds the same as to production welds. If your WPS or the AWS D1.1 preheat table requires a minimum preheat on a given base metal, thickness, and process combination, the tack welder needs to achieve that preheat before tacking.

This is the most commonly violated tacking requirement in the field. Tacks are fast — the fitter preheats the area, realizes the torch is across the shop, decides the weld will only be a two-second bead, skips preheat. Two seconds of FCAW on cold A572 at any structural thickness produces a tack in a heat-affected zone that's at hydrogen-assisted cracking risk. Restraint makes it worse. Cold tacks in restrained joints are a known initiation point for delayed cracking that only shows up days after fabrication.

The WPS documentation should specify preheat requirements for tacking, not just for production passes. See preheat and interpass temperature on a WPS for how to document these correctly in the pass schedule.

What goes on the WPS for tack welds

The AWS D1.1 Annex M WPS form doesn't have a dedicated tack weld section, but the pass schedule and notes sections should capture tack weld parameters when tacks will be incorporated:

Process — the process used for tacking (may be the same as the production pass or different)
Filler classification and diameter
Preheat minimum
Approximate tack length and size — not code-required as a field, but good practice for QC
Disposition — "incorporated into root pass" or "removed before welding"

If the tacking process differs from the production pass — for example, SMAW tacks on an FCAW production weld — the WPS should document both, and the tack welder needs to be qualified in the tacking process. The process change for tacking doesn't trigger a separate PQR, but it does require the tack welder to hold a WPQ in that process.

Qualification implications for tack welders

A welder qualified in FCAW is not automatically qualified to tack in SMAW. If your production welding is FCAW but your fitters tack in SMAW, those fitters need current SMAW WPQs.

This is a staffing and documentation problem for shops with large fit-up crews. A fitter who makes incorporated tacks on code work needs a current WPQ for the tacking process. That WPQ needs to be in the qualification matrix and on continuity tracking — a lapse in the tacking process is the same as a lapse in any other qualified process under AWS D1.1 Clause 6.4.1.

See welder qualification (WPQ) traceability to the WPS for how WPQ records should be structured, and the prequalified WPS under AWS D1.1 Clause 5 article for whether a prequalified WPS can cover tacking parameters for your process and joint type.

Common audit findings on tack welds

Third-party auditors — especially on AISC-certified fabricator audits — check tack weld documentation as a routine item. Common findings:

Tack welder not identified. Production weld records show who ran the final passes; tack records are blank or missing entirely.

No WPS specified for tacking. The production WPS doesn't mention tacking process or parameters. The auditor asks which WPS governs the tacks; the answer is often "we assumed the same WPS." That assumption should be documented, not implied.

Preheat documented for production pass, silent on tacking. The auditor infers preheat may have been skipped for tacks. Even if it wasn't, the absence of documentation is a finding.

Tacker not qualified. The person making incorporated tacks has no WPQ in the tacking process, or the WPQ lapsed before the job started.

None of these findings require major corrective action if caught before an audit. All of them generate paperwork and potential production holds when caught during one. A review of your WPS forms and weld records against these four items takes an afternoon; fixing the gaps takes less time than responding to an audit finding.

See common WPS deficiencies found in third-party audits for the broader set of WPS documentation items auditors prioritize. For digital WPS generation where tack weld pass parameters are documented in the pass schedule alongside production passes, see WPS software plans.