Which welding process has the highest deposition rate for structural groove welds?

Submerged arc welding (SAW) delivers the highest deposition rates—typically 15–25 lb/hr or more in single-wire configurations versus 6–12 lb/hr for FCAW-G and 3–6 lb/hr for SMAW. For long flat-position groove welds on plate girders or heavy columns, SAW reduces arc time dramatically. The tradeoff is equipment cost and the restriction to flat and horizontal positions.

Can you change from SMAW to FCAW on an existing WPS without a new PQR?

No. Under AWS D1.1, welding process is an essential variable. Changing from SMAW to FCAW—or adding FCAW to an SMAW WPS—requires a new or revised PQR supporting that process. A prequalified WPS under Clause 5 can be written for FCAW without a PQR if all Clause 5 requirements for FCAW are met, but a tested SMAW WPS cannot simply be relabeled.

Does changing from a double-sided V-groove to a single V-groove require a new PQR?

Not necessarily. Under AWS D1.1, joint design (groove angle, root opening, root face) affects whether a prequalified status applies but is not always a PQR essential variable in the same way process or filler metal classification is. If the joint is prequalified under Clause 5, you can change to another prequalified joint without a new PQR. For a tested procedure, check whether the new joint geometry falls within the tested range's coverage.

What is the real cost impact of switching from E7018 SMAW to FCAW-G on a large structural project?

On a large structural project with significant groove weld volume, switching from E7018 SMAW to FCAW-G with 0.045-inch wire typically reduces arc time by 40–60 percent due to higher deposition rates and elimination of electrode stub waste. The labor savings far exceed the wire and gas cost premium over E7018, especially on shop welds where FCAW setup is straightforward.

WPS Process Selection: How Joint Design Affects Weld Cost

Joint design and process choices in a WPS set weld volume and arc time. QC managers can cut fabrication cost while staying AWS D1.1-compliant — here's how.

A welding procedure specification is a code-compliance document, but it is also a production cost commitment. Every WPS decision—process, joint geometry, filler metal diameter, position qualification—translates directly into weld volume, arc time, consumable cost, and labor hours. Most CWIs and QC managers are trained to verify WPS compliance, but fewer are trained to recognize when a compliant WPS is quietly costing the shop money compared to an equally compliant alternative.

This article walks through the cost levers inside a WPS and how to evaluate them within the constraints of AWS D1.1:2025 without triggering requalification or compromising code compliance.

Weld Volume Is the Foundation of Weld Cost

Before evaluating any process or joint geometry option, quantify the weld cross-sectional area. Weld cost is proportional to the volume of deposited weld metal—more volume means more arc time, more consumables, and more passes. Every design and procedure decision that reduces cross-sectional area is a direct cost reduction.

Groove angle. A 60° included angle CJP V-groove has roughly twice the cross-sectional area of a 45° groove at the same root opening. Narrowing the groove angle from 60° to 45° on a heavy plate girder web-to-flange weld or a column splice can reduce weld volume by 20–30 percent for that joint. AWS D1.1 Clause 5 (prequalified WPS) permits included angles as low as 30° for some prequalified joint types with FCAW and SAW—check Annex B joint configurations for the applicable minimum.

Double groove vs. single groove. For thick plates (typically above 3/4 in [19 mm]), a double-sided groove weld—either double-V or double-J—dramatically reduces weld metal volume compared to a single-V taken from one side. A symmetric double-V uses roughly half the weld metal of a full single-V. The constraint is access: double-sided welding requires back-gouging or back-weld access to the second side, which may not always be practical for closed sections or structural configurations with limited access.

J-groove vs. V-groove. A J-groove has a curved lower face that reduces the included angle at the root and significantly reduces the total weld volume compared to a straight V at the same plate thickness. AWS D1.1 permits J-groove prequalified joints in Annex B. The machining cost to produce a J-groove prep is higher than a simple flame or plasma cut V-groove—this tradeoff is worth evaluating on thick plate production runs where the reduced weld volume over many joints exceeds the setup cost difference.

PJP instead of CJP. If the structural engineer has specified CJP but the loading is not tension-critical, it is worth a conversation with the EOR about whether PJP is acceptable. A PJP groove weld typically uses 40–70 percent of the weld metal of the CJP in the same joint. This is a design change, not a procedure change, and requires EOR approval—but for connections with low tension demand, it is a real cost lever.

Process Selection: Deposition Rate and Operator Factor

The cost difference between processes is primarily deposition rate (lb deposited per hour of arc-on time) and operator factor (percentage of shift the welder is actually welding). Together they determine how many labor hours go into each pound of weld metal deposited.

SMAW (Stick): Lowest deposition rate (typically 2–5 lb/hr at normal structural electrode diameters), lowest operator factor (stop-start to change electrodes, chip slag between passes), highest stub loss (10–15 percent of each electrode discarded). SMAW is the most flexible process—all positions, no shielding gas, minimal equipment—but it is the most expensive per pound of deposited weld metal in a production environment.

FCAW-G (Flux-cored, gas-shielded): The workhorse of modern structural fabrication. Deposition rates of 8–15 lb/hr with 0.045 in or 1/16 in wire in flat and horizontal; lower in vertical and overhead. Operator factor is higher than SMAW because the wire is continuous—no stub changes, less inter-pass downtime. FCAW-G with E71T-1 or E71T-9 wire is the cost-optimal choice for a large fraction of structural groove and fillet welds.

SAW (Submerged Arc): The highest deposition rates available in structural welding—15–30 lb/hr in single-wire configurations, higher with tandem or twin-wire setups. SAW is limited to flat (1G) and horizontal (2G) positions. For long groove welds on plate girders, built-up columns, and flat plate assemblies that can be turned, SAW delivers the lowest cost per pound deposited of any process. The equipment investment is significant, but for shops with steady plate girder volume, the return is clear.

GMAW (MIG): Solid wire GMAW in short-circuit transfer (STT) is common for root passes on open-root butt joints. Spray transfer is limited to flat and horizontal but delivers high deposition rates without slag. Metal-cored wire GMAW-C is increasingly used for fillet welds at higher deposition rates than conventional solid wire without flux overhead.

GTAW (TIG): Low deposition rate, used for root passes requiring exceptional quality (stainless, thin gauge, back-purge applications). Not a cost-competitive option for production structural carbon steel work.

Wire Diameter and Its Effect on Pass Count

Within a single process (FCAW-G, for example), wire diameter is a meaningful cost lever that often gets overlooked.

Larger diameter wire runs at higher amperage, deposits more per pass, and completes a given groove volume in fewer passes. A 1/16 in FCAW-G wire deposits roughly 50–70 percent more per unit time than 0.045 in wire at comparable travel speeds. Fewer passes means fewer interpass cleaning cycles, less arc start/stop time, and lower total arc time per joint.

The constraint is that larger wire at higher heat input can affect HAZ properties and may interact with CVN supplementary essential variables (Table 6.8 of AWS D1.1:2025). For CVN-required joints, the heat input range tested in the PQR limits how aggressively you can push deposition rate. Rule library based on AWS D1.1:2025; verify against your governing edition.

Wire diameter is an essential variable under AWS D1.1 Table 6.6. Changing diameter category (e.g., from 0.045 in to 1/16 in) requires either a supporting PQR or a new prequalified WPS written for the larger diameter. Ensure the PQR supports the wire diameter you want to run before committing to it in production.

Preheat Cost: More Than Just Gas

Preheat is often treated as a binary compliance issue (did we preheat or not?), but preheat is a real production cost with process selection implications.

High preheat temperatures (250°F+ for thick A572 Grade 65 or A514) extend the heat-up time before arc start, require maintained preheat throughout the joint, and restrict work on adjacent areas. The combination reduces effective production rate even when the welder is qualified and the WPS is in order.

Process choices affect preheat requirements indirectly through heat input. SAW at high heat input raises the interpass temperature rapidly, which can allow relaxation of the strict minimum preheat once the joint is up to temperature—but it also risks exceeding maximum interpass temperature on CVN-qualified joints if not monitored.

Low-hydrogen process selection (E7018-H4, FCAW-G with H4 or H8-rated wire) is the mechanism that reduces preheat requirements on borderline carbon equivalent steels. For steels near the CE boundary where preheat could go either way, specifying the lowest hydrogen filler metal classification available can eliminate a preheat requirement entirely—which eliminates the production cost of preheat.

Joint Fit-Up Tolerance and Its Impact on Rework Cost

A WPS can be perfectly selected for cost, and still produce expensive welds if the fit-up is consistently out of tolerance. Root openings beyond the specified range fill with extra weld metal (increased volume) or require repair. Gaps in excess of AWS D1.1 Table 6.1 tolerances for prequalified joints must be repaired or re-assessed before welding.

The production cost of poor fit-up compounds across three phases: rework of the joint before welding, extra weld metal to bridge an oversize gap, and increased distortion from the higher heat input needed to fill the gap. A CWI who tracks fit-up rejection rates and links them back to joint preparation methods will find recurring cost drivers that no WPS optimization can fix.

Tighter fit-up tolerance correlates directly with lower weld cost, fewer repair cycles, and less distortion-correction labor. Investing in quality joint preparation (plasma or submerged-arc cut edges versus oxy-fuel on critical joints, dedicated fit-up fixtures for repeated connection types) reduces total weld cost more reliably than optimizing the filler metal selection.

Where to Start the Cost Review

For a QC manager or CWI assigned to reduce weld costs on a structural project, a practical order of attack:

Identify the highest-volume weld joints by cross-sectional area. The top five joint types by volume typically represent 50–70 percent of total weld cost. Start there.
Verify that the process and wire diameter in the current WPS represent the most efficient option the PQR supports. Many shops run 0.045 in FCAW-G when they have PQR coverage for 1/16 in.
Check groove geometry against Annex B options. If you are running 60° V-grooves and Annex B permits 45° prequalified, write a new prequalified WPS for the narrower groove.
Evaluate double-sided groove options for joints in thickness ranges where both-side access is feasible.
Track fit-up rejection rates. If more than 5 percent of joints require fit-up repair before welding, the fit-up process is a higher-priority cost driver than process selection.

The process and joint design choices in your WPS are not locked in at bid time. With proper PQR coverage or prequalified alternatives, the procedure library can be tuned for cost throughout a project lifecycle.

For more on the qualification mechanics that gate these changes, see our article on WPS requalification triggers and our guide on building a multi-project WPS library that supports process flexibility. Ready to manage your WPS/PQR records and process coverage in one place? See our pricing.