# Submerged arc welding

SAW process selection: wire/flux combinations, polarity, joint tracking, flux recovery and moisture control, electrical planning and weld acceptance.

Reviewed: 2026-11-01

Tags: processes, welding, arc-welding, saw

A hypothetical steady arc at **30 V**, **600 A** and **600 mm/min** gives **18 kW** nominal electrical power and **1.80 kJ/mm**. A **1,000 mm** traverse takes **100 s** and uses **1.80 MJ** nominally. At **750 mm/min**, the estimate is **1.44 kJ/mm**. Verify thermal efficiency, waveforms, multiple-arc timing and joint properties separately.

Granular flux blankets the arc, forms slag and can add alloying constituents. TWI describes solid-wire, cored-wire and strip variants, generally mechanized without separately supplied shielding gas. [TWI, What is Submerged-arc Welding?](https://www.twi-global.com/technical-knowledge/faqs/faq-what-is-submerged-arc-welding)

The arc and pool are normally hidden. Joint preparation, wire positioning and controlled settings therefore matter even when the bead cannot be watched directly. A stable machine display is not evidence that the wire stayed over the joint or that every pass fused correctly.

## Define the process configuration

Specify the number and arrangement of electrodes, wire or strip type, power-source/control configuration, polarity/waveform, flux delivery and recovery, work movement and joint tracking. Single-wire, tandem and additional-wire arrangements are different process configurations, not interchangeable productivity settings. [TWI, process variants](https://www.twi-global.com/technical-knowledge/faqs/faq-what-is-submerged-arc-welding)

Confirm that the joint orientation and equipment contain the flux and molten pool. Resolve seam access, backing/root support, starting and run-off regions, component rotation or travel, and the method of removing slag between passes. A long straight demonstration does not establish capability at a start, stop or circumferential closure.

| Manufacturing input | What to resolve |
| --- | --- |
| Base materials, condition and thickness | Joint metallurgy and thermal/procedure requirements |
| Joint profile, fit-up, root and position | Electrode access, support and fusion requirements |
| Wire and flux identities | Qualified deposited-metal combination |
| Electrode arrangement and power controls | Applicable settings, tracking and interaction |
| Final condition and service | Examination, heat treatment and acceptance |

These are enquiry inputs, not a universal SAW schedule.

## Qualify wire and flux together

TWI explains that fluxes are formulated for compatible electrodes and that flux/weld-pool reactions affect chemistry and properties. Its “active” flux discussion links manganese/silicon transfer with electrical conditions. A flux is not merely inert material poured over any wire. Substitution can change the deposited metal even if the arc remains stable. [TWI, SAW process and flux types](https://www.twi-global.com/technical-knowledge/job-knowledge/submerged-arc-welding-process-005?vAction=swpTextOnly)

ISO **14171:2016**, edition 3, July 2016, classifies electrode/flux combinations and weld metal for specified non-alloy and fine-grain steels, in as-welded and post-weld heat-treated conditions. It explicitly allows one flux to be classified with different electrodes and separately classifies solid-wire composition. Thus a wire classification alone does not establish every combination's impact or strength performance. Its current record identifies revision work; the committee draft is not a published replacement. [ISO 14171:2016](https://www.iso.org/standard/68753.html)

Specify actual manufacturer/product, classification and applicable edition, diameter, lot/traceability, and the tested delivery condition. Confirm base-metal dilution, required toughness, corrosion/service conditions and subsequent heat treatment through the governing procedure. A catalog typical value is not a joint design allowable.

## Polarity and setup influence more than deposition

TWI's SAW polarity guidance describes DCEP as commonly producing greater penetration, while DCEN can increase electrode melting and reduce penetration/dilution in applications such as surfacing. It also explains that polarity changes flux/wire consumption and therefore potential alloy transfer. These are process trends, not permission to reverse polarity in a qualified procedure. [TWI, electrode polarity in SAW](https://www.twi-global.com/technical-knowledge/faqs/faq-what-is-the-effect-of-the-electrode-polarity-in-sa-submerged-arc-welding)

The same guidance describes AC use to reduce magnetic interactions in tandem systems. Identify which arc uses which waveform and preserve their spacing and orientation. Settings developed for one head arrangement do not automatically qualify another. [TWI, tandem and AC considerations](https://www.twi-global.com/technical-knowledge/faqs/faq-what-is-the-effect-of-the-electrode-polarity-in-sa-submerged-arc-welding)

Record wire-feed/current controls, voltage, electrode extension, travel, joint alignment and flux coverage together with force/support conditions where relevant. Define preheat, interpass control, pass sequence and postweld treatment for the actual application. These inputs cannot be replaced by a single nominal energy-per-length number.

## Original electrical-energy example

Assume a hypothetical steady DC arc at **30 V**, **600 A**, and **600 mm/min travel**. Ignore transients and all losses:

- Nominal electrical power = 30 × 600 = **18,000 W**.
- Travel speed = 600 / 60 = **10 mm/s**.
- Electrical energy per length = 18,000 / 10 = **1,800 J/mm = 1.80 kJ/mm**.
- A **1,000 mm** traverse takes **100 s**, corresponding to **1.80 MJ** nominal electrical energy.

At 750 mm/min and unchanged voltage/current, the nominal value becomes **1.44 kJ/mm**. This original calculation is not absorbed joint heat or a recommended procedure. Actual waveforms, thermal efficiency, penetration, flux reactions and start/stop behavior are excluded. For multiple arcs, record the actual electrical contribution and timing of each rather than using one head's display for the entire system. Equal calculated values do not establish equal weld properties.

## Flux storage, recovery and contamination

Lincoln's **Modern SAW**, publication **C5.50, issue 11/19**, explains that flux moisture can contribute to hydrogen-related cracking, porosity and slag-removal problems. It directs users to current handling instructions rather than treating the historical guide as the final authority for every product. [Lincoln Electric, Modern SAW, section 10](https://ch-delivery.lincolnelectric.com/api/public/content/c6c88b1a1fd5495c9a6c9fe887750379?v=41bf5aa5)

Its **C1.10 catalog, issue 10/23**, distinguishes storage by packaging/application and describes recovering **non-consumed flux** while removing slag, metal, scale and excess fines. It also lists product exceptions in its re-drying guidance. Recovered granular flux is not the same thing as crushed slag, and an oven cycle must come from the actual producer/product instructions. Do not assume one temperature or fresh/recovered ratio qualifies every flux. [Lincoln Electric, storage/handling and recycling, printed M-14](https://ch-delivery.lincolnelectric.com/api/public/content/f5e38ae6ebf441829d73d7b1a404818b?v=84bee2da)

Preserve flux identity through storage, recovery and replenishment. Define the disposition of mixed, contaminated or moisture-exposed material and how the recovery equipment affects particle condition. The presence of a flux hopper does not establish low-hydrogen control. Use current consumable SDS and equipment instructions for handling, fumes, electrical exposure and hot slag; the covered arc does not eliminate the operation's hazards.

## Qualification, acceptance and handoff

Select the governing application standard and procedure/personnel qualification requirements for the actual materials and process variant. Specify required weld geometry, penetration/fusion, permitted imperfections, examination coverage and test timing. Include any delayed examination, heat treatment, machining and repairs required by that application.

Separate surface appearance and slag removal from internal conformance, material properties and service performance. A high deposition rate does not prove fusion; a passing tensile specimen does not establish every impact or fatigue requirement. Define how starts, stops, roots and closure regions are represented in qualification and production inspection.

Provide the controlled joint drawing, base and consumable traceability, wire/flux combination, actual electrode and power configuration, tracking/setup, thermal controls, recovery/maintenance plan and final acceptance records. Evaluate changes in flux, polarity, wire arrangement or delivered heat-treatment condition against that qualified route.

## Source versions

Reviewed 2026-11-01. Lincoln's actual footers identify C5.50 **11/19** and C1.10 **10/23**; they are historical source versions, with current product instructions required for operation. ISO's published edition is identified above. No separately verified technical issue date is assigned to the cited TWI live guidance. The electrical calculation and handoff recommendations are original and supply no universal settings or joint allowable.

## Related reference

[Welding methods](index.md)