FCAW-G Out-of-Position WPS: Essential Variables Under AWS D1.1
FCAW-G vertical-up and overhead WPS requirements under AWS D1.1: electrode designators, wire diameter as an essential variable, shielding gas, and groove weld restrictions.
Flux-cored arc welding with external shielding gas (FCAW-G) is among the most productive processes available in structural fabrication, but moving from flat and horizontal work to vertical or overhead positions introduces a set of essential variable and code restriction issues that trip up even experienced WPS writers. If your shop welds in the 3F or 4F position with FCAW-G—or if projects are starting to require it—here is what the WPS program needs to address.
Electrode Designator and Position Eligibility
The AWS A5.20 classification system for carbon steel FCAW electrodes encodes position eligibility directly in the designation. The digit immediately following the strength number indicates welding position:
0: flat and horizontal fillet only (1F, 2F)
1: all positions (1F, 2F, 3F, 4F)
An E70T-1C electrode (designator "0") is limited to flat and horizontal. An E71T-1C electrode (designator "1") is rated for all positions including vertical-up and overhead. Specifying an all-position electrode does not, by itself, authorize out-of-position work—the WPS must be supported by a PQR that tested those positions. But specifying a flat/horizontal-only electrode in a WPS written for vertical-up production is a procedural deficiency that will appear immediately in any competent audit.
Electrode designator is an essential variable under AWS D1.1:2025 Table 6.6. Changing from an E71T-1C to an E71T-9C (a different designator suffix, even if both are all-position capable) constitutes an essential variable change that requires PQR support for the new designation.
Rule library based on AWS D1.1:2025; verify against your governing edition.
Wire Diameter as an Essential Variable
Wire diameter is explicitly listed as an essential variable in Table 6.6. This catches many fabricators off guard—they qualify a WPS at 0.052-inch wire diameter in the 3F position, then switch to 0.045-inch wire on the production floor to improve positional control. The WPS no longer supports the actual parameters being used.
For out-of-position FCAW-G work, typical industry practice runs:
Vertical-up and overhead fillet welds: 0.035 to 0.052 inch (0.9 to 1.4 mm) — smaller diameters reduce weld pool volume and improve control at reduced heat input
Flat and horizontal work: 0.052 inch to 3/32 inch (1.4 to 2.4 mm) — larger diameters increase deposition rate
The PQR must be run at the wire diameter intended for production. If your shop uses 0.045-inch wire for 3F production welding, the PQR must use 0.045-inch wire. A PQR run at 0.052-inch wire does not qualify 0.045-inch production welding, because wire diameter is an essential variable.
From a practical standpoint, it is worth qualifying at a specific wire diameter for out-of-position work and maintaining discipline on the production floor to use that diameter. See Wire Feed Speed vs. Amperage in GMAW and FCAW WPS Documentation for the relationship between wire feed speed and heat input in FCAW-G procedure writing.
The CJP Groove Weld Restriction for Vertical-Down
AWS D1.1 prohibits FCAW-G in the vertical-down (3G downward) position for complete joint penetration groove welds. This restriction exists because vertical-down welding with flux-cored wire produces incomplete fusion and slag entrapment patterns that are not reliably detectable by visual inspection alone, and the consequences in CJP structural welds are severe.
The prohibition applies specifically to CJP groove welds. Fillet welds in the vertical-down position with FCAW-G are not universally prohibited but are subject to the same electrode designator and WPS qualification requirements. Some electrode designators are classified for vertical-down fillet welding by their manufacturers; the WPS must reflect the tested position and designator. See FCAW-G Vertical-Down CJP Groove Weld Prohibition Under AWS D1.1 for the clause basis and inspection implications.
Shielding Gas Changes Require Requalification
Shielding gas composition is an essential variable in Table 6.6. A WPS qualified with C25 (75% Ar / 25% CO2) does not cover production welding with 100% CO2, even if both gases are nominally acceptable for FCAW-G. The arc characteristics, penetration profile, and spatter level differ enough that the change requires a new PQR.
For out-of-position welding, gas blend matters more than it does in flat production work:
100% CO2 produces a more turbulent arc and higher spatter rate; managing an overhead weld pool with 100% CO2 demands more welder skill and produces less consistent results
Ar/CO2 blends (C25 is the most common) give a softer arc, more stable puddle, and better weld profile out of position
Flow rate verification is more important in positional work because drafts and restricted access reduce effective gas coverage; the WPS should specify both the gas blend and the minimum flow rate
If your WPS currently lists 100% CO2 and your welders are having difficulty controlling the pool in vertical or overhead positions, the right fix is a new PQR with the Ar/CO2 blend—not an undocumented change on the floor. See Shielding Gas Essential Variables Under AWS D1.1 for the full requalification scope of gas changes.
PQR Testing for Out-of-Position FCAW-G
If you are writing a tested WPS under Clause 6 for vertical or overhead FCAW-G work, the PQR must include test plates welded in those positions. For a vertical-up fillet (3F) WPS, the test plate is welded in the 3F position and subjected to the mechanical testing required by Clause 6: bend tests for groove welds, macro examination or nick-break tests for fillet welds.
Position tests tend to drive smaller wire diameter, lower wire feed speed, and reduced voltage compared to flat/horizontal parameters for the same electrode. Document the actual parameters used in the PQR test (wire feed speed, voltage, travel speed, wire diameter, gas blend and flow rate) because these form the qualified range. Any production deviation outside that range either requires requalification or requires a WPS revision that stays within the tested envelope.
For prequalified FCAW-G procedures under Clause 5, note that the prequalified provisions have their own process and electrode limitations; out-of-position prequalified FCAW-G work is restricted to electrode types and wire diameters that the code has specifically validated. Review Clause 5 carefully before writing a prequalified WPS for 3F or 4F FCAW-G production.
FCAW-G Out-of-Position in WPS Documentation
The WPS form (Annex J Form J-1) must clearly state the applicable positions and the parameters qualified in those positions. Common documentation gaps for out-of-position FCAW-G:
Position not listed: the WPS lists "flat/horizontal" by habit and the 3F production work is never formally covered
Wire diameter range not stated: the form shows "0.045–0.052 inch" when the PQR only tested 0.052 inch
Voltage range derived from flat parameters: vertical-up work typically runs 1–3 V lower than the flat parameters; a WPS that shows only the flat-position voltage range leaves the welder guessing
Gas flow rate omitted: especially important in positional work where coverage is less reliable
A well-written FCAW-G WPS for out-of-position work should show a separate column or section for 3F/4F parameters distinct from the 1F/2F ranges, making it immediately clear to the welder and the CWI what parameters apply in each position.
Connecting to Your WPS Library
If your shop welds FCAW-G across multiple positions on the same project, audit your WPS library for these gaps:
Confirm the electrode designator shown on each WPS supports the production positions listed
Verify the wire diameter on the floor matches the diameter shown on the WPS
Check that the shielding gas blend and flow rate on the WPS match production practice
Confirm no WPS lists vertical-down FCAW-G for CJP groove welds
A digital WPS system can flag these mismatches before they become audit findings. See our pricing page to learn how a structured WPS platform maintains essential variable traceability across your procedure library.
Summary
FCAW-G out-of-position welding under AWS D1.1 requires all-position electrode designators, wire diameter and shielding gas matched to the PQR, and a WPS that explicitly covers the 3F and 4F positions tested. Vertical-down CJP groove welds are prohibited regardless of electrode designation. Wire diameter is a Table 6.6 essential variable, so switching between diameters on the production floor without WPS revision is a procedural deficiency. Address these items at the WPS writing stage and you avoid the common finding of out-of-position production work that has no supporting qualification.
FAQ
Frequently asked.
Can FCAW-G be used in the overhead position under AWS D1.1?
Yes. FCAW-G electrodes with an all-position designator (the digit '1' in the AWS A5.20 classification, as in E71T-1C) can be used in the overhead fillet position. The supporting WPS and PQR must include the overhead position, and the wire diameter must be within the range qualified by the PQR test.
Is vertical-down welding with FCAW-G permitted for CJP groove welds under AWS D1.1?
No. AWS D1.1 prohibits FCAW-G in the vertical-down progression for complete joint penetration groove welds. Vertical-down fillet welds with FCAW-G are permitted only with specific electrode designators and where the WPS and PQR support that progression.
Is wire diameter an essential variable for FCAW-G in AWS D1.1?
Yes. Wire diameter is an essential variable under Table 6.6 of AWS D1.1:2025. Changing from a 0.045-inch to a 0.052-inch wire, or from a 0.052-inch to a 3/32-inch wire, requires a new PQR or a separate test unless the change is within the qualified range documented in the supporting PQR.
Does shielding gas composition affect FCAW-G out-of-position welding?
Yes, though shielding gas composition is a separate essential variable. Mixed argon-CO2 blends typically provide better arc stability and a more controllable weld pool in vertical and overhead positions compared to 100% CO2. Any gas change beyond the limits set in the WPS and Table 6.6 requires requalification.