Can I cover GMAW root and SAW fill on a single WPS document, or do I need two separate WPS files?

AWS D1.1:2025 permits a single WPS to list multiple welding processes applied in sequence to the same joint. There is no code requirement to produce separate WPS documents for each process when both are used together on one joint in production. Many shops use a single document with clearly separated parameter columns for each process; others maintain separate WPS documents and reference both on the weld map. Either approach is acceptable provided the essential variable envelope for each process is properly recorded.

If I change my GMAW wire diameter for the root pass, do I also have to requalify my SAW fill process?

No. The essential variables in AWS D1.1:2025 Table 6.6 apply independently to each process listed on the WPS. Changing an essential variable for the GMAW root process invalidates only the GMAW qualification — the SAW fill process qualification is unaffected, provided the SAW parameters remain within the PQR-qualified range.

The PQR test plate was welded entirely with GMAW. Can I use it to support a combined GMAW root and SAW fill production WPS?

No. AWS D1.1 requires the PQR to represent the production WPS. A PQR run entirely with GMAW does not capture the heat profile produced by SAW fill passes, and the mechanical test specimens reflect only GMAW-deposited weld metal. To support a GMAW+SAW combination WPS, the PQR test weld must use both processes in the same sequence planned for production.

GMAW Root and SAW Fill: Qualifying a Multi-Process WPS

Q: Who needs to be qualified when GMAW root and SAW fill are performed by different personnel?

Both must hold valid qualification credentials. The welder running the GMAW root needs a WPQ covering GMAW in the required position. The SAW fill process is typically performed by a welding operator (machine welding), whose qualification differs from welder performance qualification. Both sets of credentials must be traceable to the WPS and must appear on the weld map or weld record for the joint.

Heavy plate fabrication often pairs GMAW root passes with SAW fill and cap. Here's how AWS D1.1:2025 treats multi-process WPS qualification and PQR test requirements.

Heavy plate fabrication — think 1½-inch web plates on plate girders, 2-inch column flanges on built-up sections — creates a welding procedure challenge that no single process handles perfectly. GMAW gives you positional flexibility and controlled root fusion in tight fit-up conditions. SAW delivers high deposition rates and consistent bead geometry once the joint is open. Combining them on a single joint is standard practice in structural fab shops doing deep-groove CJP welds. Doing it with a code-compliant WPS takes planning.

Why the Combination Makes Sense

Open the root of a deep groove weld in flat position and a SAW head can deposit fill and cap passes in a fraction of the time it takes SMAW or FCAW. The problem is the root pass itself: SAW equipment cannot easily reach into tight root openings and maintain the penetration control needed for a sound CJP root bead. GMAW — particularly short-circuit or pulsed transfer — can place a controlled root bead in joint openings as tight as ¼ inch and produce adequate fusion without burn-through.

In production, the combination typically plays out as:

GMAW for the root bead and hot pass, often run in the 1G or 2G position
SAW for the remaining fill passes and cap, run in flat position after the joint has been fit and the root is established

The result is a faster overall cycle time with better quality control at the most critical location in a CJP weld: the root. The SAW deposition rate advantage is captured for the bulk of the joint volume, while GMAW handles the geometry-sensitive portion.

One WPS or Two?

AWS D1.1:2025 permits a single WPS to list multiple welding processes applied in sequence to the same joint. There is no code requirement to produce separate WPS documents for each process when both are used together on one joint in production. A single document can state: "Process 1 — GMAW per the following parameters (root and hot pass); Process 2 — SAW per the following parameters (fill and cap passes)."

The practical argument for a single document is traceability. If a welder is running GMAW and hands off to a welding operator running the SAW head, both need a single authoritative document to reference for that joint. Splitting into two WPS documents introduces the risk that the SAW WPS is pulled without the GMAW root requirements being visible — or that the GMAW WPS is archived once the root is complete, creating a documentation gap.

The alternative is intentional: some shops maintain separate GMAW and SAW WPS documents and reference both on the weld map for the given joint. Either approach is acceptable under the code, provided the essential variable envelope for each process is independently documented and traceable.

For an overview of how WPS documents relate to PQR records, see WPS vs. PQR vs. WPQ — what each document does.

Essential Variables Apply Per-Process

This is the point most shops miss when writing a multi-process WPS: the essential variables from AWS D1.1:2025 Table 6.6 apply independently to each process. The GMAW column governs the root pass parameters; the SAW column governs the fill and cap parameters. If you change an essential variable for the GMAW root process, you are not automatically forced to requalify the SAW fill process — the change only invalidates the qualification for the process where the variable changed.

Conversely, if a third-party auditor finds that your SAW wire diameter or flux classification changed from what's on the PQR, your SAW qualification is in question — but the GMAW root documentation is unaffected if that process's variables are unchanged.

In practice, your WPS must clearly delineate which variables belong to which process. A two-column format — one column for GMAW parameters, one for SAW parameters — is cleaner than trying to footnote which amperage range applies to which process. At minimum, the process identifier must precede each parameter block.

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

Building the PQR for a Combination Procedure

AWS D1.1 requires the PQR to represent the production WPS. For a multi-process combination, the PQR test weld must be made using both processes in the same sequence planned for production.

You cannot run a full GMAW PQR and a full SAW PQR separately and then claim they together support a combined GMAW+SAW WPS — because neither individual PQR reflects the combined heat profile and microstructural effects of the actual production sequence. The weld metal deposited by SAW fill passes over a GMAW root experiences a different thermal history than weld metal deposited in an all-SAW test plate.

The PQR test plate for a GMAW root + SAW fill combination procedure:

Is welded with GMAW through the root bead and hot pass, representing the production root sequence
Then completed with SAW for the remaining fill passes and cap
Is subjected to the full mechanical test battery (tension, guided bend) on the completed, combined test weld

All essential variables for each process must be recorded on the PQR exactly as run during the test. That means separate amperage, voltage, travel speed, and heat input records for the GMAW passes and the SAW passes.

For more on what mechanical testing the PQR requires, see guided bend test requirements under AWS D1.1.

Thickness Range from a Combination PQR

The PQR test plate thickness sets the production qualification range for the combination as a whole. Standard AWS D1.1 rules apply: a PQR test plate ¾ inch or thicker qualifies for production base metal at any thickness at or above the minimum thickness covered by the WPS, with process-specific limits.

For most heavy plate combination procedures, test on material representative of the production range — typically 1 inch to 2 inches — rather than on minimum-thickness plate. Thicker PQR plates give wider qualification latitude and better represent the heat conditions, interpass temperatures, and cooling rates your production welders will encounter in the shop. A PQR plate that is too thin can leave you without qualification for the heavy section work where GMAW+SAW is most needed.

Heat Input Documentation Across Both Processes

SAW runs significantly higher heat input per pass than GMAW. On a combination WPS, the heat input must be documented for each process separately, and the maximum qualified heat input for each process must be honored in production. A heat input limit that is adequate for the GMAW root bead is nowhere near the SAW parameters.

A common audit deficiency: the WPS shows a single heat input range that does not distinguish between processes. When a CWI asks "what's your maximum qualified heat input for the SAW fill passes?" the answer must be traceable to the SAW parameters recorded on the PQR — not to a combined range that blurs the two processes together.

For CVN-toughness-required welds, heat input becomes a supplementary essential variable under AWS D1.1:2025 Table 6.8. On a combination procedure, this essential variable applies independently per process, which is another reason to keep the parameter documentation cleanly separated in the WPS.

For SAW-specific essential variable requirements, see SAW essential variables under AWS D1.1. For multi-pass sequence documentation practices, see multi-pass weld sequence documentation.

Production Tracking and Personnel

On a combination WPS, the personnel qualification section requires careful attention. The welder running the GMAW root and the welding operator running the SAW head may be different individuals with different qualification credentials.

SAW is performed by a welding operator (machine welding), whose qualification requirements and test procedures differ from welder performance qualification. On the weld record or weld map for a joint welded under a GMAW+SAW combination WPS, both the welder's stamp (GMAW root) and the welding operator's identifier (SAW fill) should appear — or at minimum be traceable through the production record.

Getting the welder versus welding operator distinction wrong is a recurring finding in AISC certification surveillance audits. Qualification of a welder for GMAW does not automatically qualify that individual to operate a SAW machine in a welding-operator capacity. See AISC certification audit readiness for how auditors review multi-process combination procedures.

Managing a multi-process WPS library — with PQR traceability, per-process essential variable tracking, and welder qualification matrices — is exactly what WPS Welding is built for.