FCAW-S Prequalified WPS Limits Under AWS D1.1:2025

Why FCAW-S Prequalification Has a Narrower Scope

Self-shielded flux-cored arc welding (FCAW-S) is the backbone of much structural field welding — especially in wind-exposed and cold-climate conditions where an external shielding gas cylinder is impractical. E71T-8 and E71T-11 electrodes under AWS A5.20 dominate the D1.1 market for field fillet welds on beams, deck attachment, and miscellaneous connection work.

But when a CWI or welding coordinator reaches for Clause 5 of AWS D1.1:2025 to write a prequalified WPS, FCAW-S runs into hard limits that FCAW-G does not. Understanding where those limits fall — and why — keeps a fab shop or erection contractor from presenting an invalid WPS on a third-party audit.

What "Prequalified" Actually Means for FCAW-S

AWS D1.1 Clause 5 defines prequalified WPS as procedures that comply with all stipulated requirements and are therefore exempt from qualification by test under Clause 6. Prequalification is not a blanket exemption — it means the procedure falls within a boundary that AWS has already implicitly validated through years of standardized industrial practice.

For FCAW-S, prequalification applies to:

• Fillet welds in flat (1F) and horizontal (2F) positions, and in vertical (3F) and overhead (4F) with electrode classifications specifically listed as prequalified for those positions.
• Partial joint penetration (PJP) groove welds in flat and horizontal positions, using prequalified joint geometries from Annex B.

What FCAW-S prequalification does not cover:

• Complete joint penetration (CJP) groove welds in any position.
• CJP groove welds with steel backing (back-gouged and back-welded CJP configurations are excluded as well).

This reflects the AWS position that FCAW-S electrode chemistry and its self-generated flux shield have historically shown greater porosity and fusion variability in groove root passes compared with gas-shielded processes — a risk AWS has chosen not to prequalify away.

The CJP Groove Weld Boundary

For a structural erector or fab shop, the practical impact is direct: any CJP groove weld joint — beam-column moment connections, column splices, full-penetration stiffener welds — cannot be welded on a prequalified FCAW-S WPS.

If a connection drawing specifies a CJP groove weld and you plan to use E71T-8 or E71T-11, you need a Clause 6 test-qualified WPS. That means:

1. A formal Procedure Qualification Record (PQR) with tensile, bend, and (if required) Charpy CVN specimens.
2. A test plate welded under supervision with all essential variables recorded.
3. A third-party or in-house laboratory performing the mechanical tests per AWS B4.0.

Many erection contractors sidestep this by qualifying a SMAW E7018 or FCAW-G WPS for CJP groove connections and reserving FCAW-S for fillet welds and PJP only. That is a compliant strategy — provided the fillet weld WPS is written correctly.

Electrode Classification and the A5.36 Factor

AWS A5.20 is the traditional classification standard for carbon steel FCAW electrodes. E71T-8 means: 70 ksi minimum tensile, all positions, non-gas shielded, specific flux composition Type 8. E71T-11 is similar but without impact-test requirements.

AWS A5.36 is the newer performance-based standard. Some electrode manufacturers have migrated to A5.36 designations (e.g., E71T8-A4-CS3-H8) for the same weld deposit.

Under AWS D1.1:2025, Table 6.6 (essential variables for SMAW, SAW, GMAW, FCAW, and GTAW) had a material change: A5.36 was dropped from the GMAW/FCAW allowed list in Row 4. Rule library based on AWS D1.1:2025; verify against your governing edition. This means if your electrode is classified under A5.36 rather than A5.20, the essential variable tracking path differs — confirm the electrode's classification against what Table 6.6 specifically allows for your process in the 2025 edition.

For prequalified FCAW-S WPS work, use electrodes with a valid A5.20 E71T-8 or E71T-11 classification confirmed in the manufacturer's certificate of conformance.

Position Limits for Prequalified FCAW-S Fillet Welds

Even within fillet weld prequalification, position restrictions apply. E71T-11 is listed as prequalified for all positions (1F, 2F, 3F, 4F) for fillet welds, but E71T-8 may carry additional position qualifications depending on the specific product. Your WPS must match the electrode's classified test positions.

The practical CWI check: review the manufacturer's certification (AWS A5.20 compliance test report) and confirm that the electrode was tested and classified for the position you are welding. A manufacturer can certify to all positions or to a subset — the certificate defines the boundary, not the general designation.

Writing the Prequalified FCAW-S Fillet WPS

A valid prequalified FCAW-S WPS must include all the mandatory content from AWS D1.1:2025 Annex M (or an equivalent format accepted by the Engineer of Record), including:

• Process designation: FCAW; note as self-shielded (no shielding gas). CTWD requirements differ from FCAW-G.
• Electrode classification: A5.20 E71T-8 or E71T-11, including the H-designator if required by the toughness specification. Low-hydrogen electrodes (H4 or H8) may be required on demand-critical welds per the project specification.
• Current type and polarity: E71T-8 and E71T-11 typically run DCEN (electrode negative, straight polarity). This is the opposite of most FCAW-G electrodes — a common error on dual-process shops where operators switch between the two.
• Contact tip-to-work distance (CTWD): Self-shielded electrodes are sensitive to CTWD. Longer CTWD increases resistive preheating of the electrode, which affects slag shielding. Document the qualified range and post it at the welding station.
• Preheat and interpass temperature: per AWS D1.1:2025 Table 3.2 (or as required by the base metal group and thickness).
• Position: list only the positions supported by the prequalification pathway for your electrode type.
• Base metal: list the prequalified base metals from the applicable D1.1 table. A36, A572 Grade 50, and A992 are all within the prequalified base metal list.

What Happens When the Auditor Checks the WPS

At an AISC certification audit or a project QC review, the auditor will verify that every production WPS is either prequalified (and demonstrably in scope) or supported by a valid PQR. A FCAW-S WPS used on CJP groove welds with no supporting PQR is a finding — often a major finding under the AISC Welding Quality Control category.

The fix is not retroactive. The production welds are in question and the shop must either:

1. Retroactively qualify the procedure (the production welds remain in question until an EOR disposition is obtained).
2. Demonstrate the production welds meet another acceptance path (rare; requires EOR and possibly special inspection authority involvement).
3. Rework and re-weld.

The best time to audit your FCAW-S WPS scope is at the pre-construction WPS review, not after fabrication starts.

FCAW-S Prequalification Scope Summary

Keep a version of this reference in your WPS procedure log. When a project specification arrives calling for FCAW-S field welds, the first document check should be: does any connection detail require CJP grooves?

For a deeper look at essential variables when FCAW-S goes to test qualification, see FCAW-S vs. FCAW-G essential variables and WPS differences and the AWS D1.1 Table 6.6 essential variable reference. For the full prequalified WPS scope under Clause 5, see prequalified WPS limitations under AWS D1.1.

To maintain your FCAW-S and FCAW-G WPS libraries with prequalified vs. tested status tracked per procedure, see wpswelding.com/pricing.