FCAW-S vs FCAW-G: what evidence does a structural-steel WPS need?

Identify the actual process from the consumable and setup

“Flux-cored” alone does not identify the shielding method or qualify a procedure. FCAW-S (self-shielded) relies on the wire’s internal system for arc protection; FCAW-G (gas-shielded) uses an external shielding gas. Check the exact product classification, manufacturer data sheet, wire label and machine setup. Do not infer FCAW-S from a missing gas line on an incomplete WPS.

Lincoln Electric’s public FCAW guide describes FCAW-S as a distinct process and explicitly limits that guide to self-shielded electrodes; its machine/process references also distinguish FCAW-S and FCAW-G. Those materials help identify and source product evidence, but they are not AWS permission for a particular WPS.

Build an evidence packet for the wire actually being proposed

Do not copy a current, voltage, travel speed or gas-flow number from a broad catalog and present it as a code-required setpoint. Manufacturer operating ranges are product-specific setup evidence; the WPS still needs its own supported values and all applicable qualification conditions.

Keep the two qualification routes separate

Clause 5: FCAW is among the process categories that may be prequalified only when every applicable Clause 5 condition is met. Confirm the exact AWS A5 filler classification and suffix against the applicable filler-metal provisions, then verify the joint detail, materials, position, temperature, process controls and required written variables. For FCAW-G, separately establish the gas path under 5.6.4. A process label or manufacturer certificate alone does not establish the full prequalified WPS.

Clause 6: Start from the specific PQR’s recorded product, process, size, polarity, electrical values, position, joint, material, temperature and test results. Compare proposed changes with the applicable Table 6.6 process column and any supplementary-variable table that applies. Do not apply Table 5.5 production tolerances as Clause 6 qualification ranges, or combine unrelated PQRs to fill missing values.

For either route, resolve whether the contract or code requires CVN and whether the weld sequence creates an FCAW-S intermix condition. Where FCAW-S is deposited first and another process deposits weld metal over it, Clause 6.28 can require additional intermix CVN testing under the applicable trigger. Verify existing records for the required evidence; if the work needs new procedure or intermix testing, this WPS-preparation service does not arrange it.

A bounded example: the suffix changes the evidence task

A project proposes a named FCAW-G wire with an argon/CO₂ mixture. The useful next step is not to borrow another wire’s gas range. Record the exact AWS classification and -M status where relevant, retrieve the matching manufacturer sheet, identify the gas composition and flow, and establish which 5.6.4 route supports that combination. Then complete the rest of the Clause 5 review. If the route instead relies on a PQR, use that PQR’s actual recorded gas and variables; a manufacturer sheet cannot supply an omitted qualification value.

For a named FCAW-S wire, the same project record should show the actual self-shielded product and its manufacturer instructions. If a later process will be deposited over FCAW-S and CVN applies, pause the normal variable review and check the specific intermix evidence requirement before claiming coverage.

Useful manufacturer references

• Lincoln Electric welding guides — locate process and consumable guidance; select the exact product data sheet for the wire under review.
• Lincoln Electric AWS D1.1 certificate center — supporting certificate material, not a substitute for the project’s WPS qualification record.

Use current manufacturer documents for the specific trade product. A manufacturer’s process classification, recommended parameters or certificate is technical support evidence; only the governing code route and complete project evidence determine whether the proposed WPS is supportable.

Code basis and related guides

AWS D1.1/D1.1M:2025 base edition plus the registered 2026-07-28 base-edition errata, excluding AMD1. Primary provisions include 5.5–5.6, Tables 5.4–5.5, 5.6.4, Clause 6 Tables 6.6 and 6.8, and 6.26–6.28 where CVN/intermix conditions apply. Verify the current controlled code and project edition.