{"id":4050,"date":"2026-05-10T05:23:45","date_gmt":"2026-05-10T05:23:45","guid":{"rendered":"https:\/\/zxweldingrobot.com\/?p=4050"},"modified":"2026-05-10T05:23:45","modified_gmt":"2026-05-10T05:23:45","slug":"submerged-arc-welding","status":"publish","type":"post","link":"https:\/\/zxweldingrobot.com\/es\/blog\/submerged-arc-welding\/","title":{"rendered":"Soldadura por arco sumergido (SAW): Gu\u00eda rob\u00f3tica de p\u00f3rtico para placas pesadas"},"content":{"rendered":"
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Submerged arc welding<\/a> – shortened SAW and sometimes known as sub arc or subarc welding – is the workhorse of the heavy-plate structural steel, shipbuilding and pressure-vessel world. Filed in 1935 and improved for nearly 100 years it deposits a thick granulated flux blanket over the weld zone such that the arc burns invisibly beneath, providing deposition rates beyond even the most skilled manual process. In this today’s guide we describe the fundamentals, installed equipment, field applications and the robotic gantry workstation that transforms a high-deposition process into a repeatable, hands-free production line.<\/p>\n

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Quick Specs: Submerged Arc Welding<\/h3>\n\n\n\n\n\n\n\n\n\n\n
Process<\/td>\nContinuously fed wire arc beneath granular flux blanket<\/td>\n<\/tr>\n
Deposition rate<\/td>\nUp to 45 kg\/h (100 lb\/h) \u2014 about 9\u00d7 SMAW<\/td>\n<\/tr>\n
Current range<\/td>\n300\u20132,000 A single arc; up to 5,000 A multi-arc<\/td>\n<\/tr>\n
Wire diameter<\/td>\n1.6 \u2013 6.4 mm (1\/16″ \u2013 1\/4″)<\/td>\n<\/tr>\n
Plate thickness<\/td>\n6 mm to 250+ mm (multi-pass on thick sections)<\/td>\n<\/tr>\n
Welding position<\/td>\nFlat (1F\/1G) and horizontal-fillet (2F)<\/td>\n<\/tr>\n
First patented<\/td>\n1935 (Lloyd T. Jones et al., US 2,043,960)<\/td>\n<\/tr>\n
Best for<\/td>\nLong, straight or rotated welds on carbon and low-alloy steel<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

What Is Submerged Arc Welding?<\/h2>\n

\"What<\/p>\n

Submerged arc welding is a fusion welding process in which a continuously fed bare or tubular wire electrode strikes an arc against the workpiece beneath a blanket of granulated flux. The flux melts in the immediate arc zone, becomes electrically conductive, and shields the weld pool from atmospheric contamination – eliminating spatter, ultraviolet flash and most welding fume.<\/p>\n

The process was originally patented in 1935 by Lloyd T. Jones and Harry Edward Kennedy and Maynard Arthur Rothermund (US Patent 2,043,960) and came into industrial use through structural steel and shipbuilding fabricators who needed a method of depositing weld metal faster than individual arc welding operators were able to manually manipulate an electrode. Nowadays the granulated flux consists of lime, silica, manganese oxide, calcium fluoride and other compounds that not only affords protective shielding but can also alloy the weld metal almost as though it were subjected to a gas tube – Reddit pressure-vessel fabricators are often heard commenting that “choosing various SAW fluxes is like adding alloy to the weld metal”.<\/p>\n

Unlike shielded metal arc welding (SMAW) where a shadow is observed by the weld operator the used tungsten or tungsten coated rod, in SAW the arc is buried beneath an uninvolved slag blanket. The weld is completed before the operator can actually view its formation in the weld pool – once the slag is chipped from the weld and the unused flux vacuumed up and reused.<\/p>\n

How the SAW Process Works (Mechanics & Key Variables)<\/h2>\n

\"How<\/p>\n

An SAW system supplies three ingredients to the weld preemptively: a filler wire, granular flux, and electricity. The wire is steadily supplied at an appropriate rate through a contact tip, flux is directed ahead of the wire from a hopper or pressurized conduit, and the electric current is delivered from a constant-voltage power source through the wire to the workpiece. When the arc strikes, the lower flux melts into a highly electrically conductive slag that carries the current and shields the molten weld pool, producing a smooth weld bead with no spatter and minimal fume. The upper flux remains granular and is recovered after each pass – anything between 50% and 90% can be used again.<\/p>\n

Arc length is held constant by a self-adjusting principle: if the height shortens, the voltage across the arc drops, the current flowing through the wires increases, and the wire melts more rapidly and if the height gets higher, vice versa. This passive property make sure SAW is mostly operated by semi or fully automatic machines – the torch control is not needed once the parameters are set up.<\/p>\n

Why Is Submerged Arc Welding Called “Submerged”?<\/h3>\n

That name refers to the arc, not the workpiece. SAW generates the arc inside a bed of granular flux – submerged in flux, not visible. There is no visible flash from the arc, there is no shower of spatter and its ultraviolet contribution is minimal. Operators don’t need a welding helmet or jacket to work near this process – a huge workplace-safety benefit that’s rare in arc welding processes.<\/p>\n

What’s the Deposition Rate of SAW?<\/h3>\n

SAW deposits from 9 – 18kg\/h (20 – 40lb\/h). Twin-wire and multi-arc set-ups can reach 45kg\/h (100lb\/h) as shown in Wikipedia’s citing of the Lappeenranta-Lahti Uni study on penetration. SMAW caps at about 5kg\/h. That 9 difference in order of magnitude is the fundamental business motivation that, a century after its invention, SAW is still the default heavy-plate process.<\/p>\n

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\ud83d\udcd0 Engineering Note: Five Controlled SAW Variables<\/strong><\/p>\n
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  1. Wire feed speed \u2014 primary control over welding current<\/li>\n
  2. Arc voltage \u2014 controls bead width and reinforcement<\/li>\n
  3. Travel speed \u2014 controls heat input and bead profile<\/li>\n
  4. Electrode stickout (ESO) or contact-tip-to-work distance (CTTW) – influences current density<\/li>\n
  5. Polarity, current: DC, AC or multi-electrode variable-balance AC<\/li>\n<\/ol>\n<\/div>\n

    Essential Equipment & Consumables (Power, Wire, Flux, Carriage)<\/h2>\n

    \"Essential<\/p>\n

    Every SAW power set-up has four bits. Selecting any one of them in isolation tends to produce a mismatched cell that underperforms.<\/p>\n

    Power supply: most modern single-wire SAW uses a constant-voltage DC power supply. DC variable-balance, with multiformate AC is needed for twin- or multi-wire set-ups where magnetic-arc-blow has become a problem. Capacities go up to 800A for thin sections, and 1500A for heavy plate; multi-arc systems are usually two or three supplies working together.<\/p>\n

    Wire-feeder: high-torque pushes the solid or cored wire through the contact tip constantly, into the prepared groove on the work surface. The wires are copper-coated to enable current transfer, and to prevent oxidation between uses. Wires are spooled in straight lengths or in coils.<\/p>\n

    Flux delivery: granular flux is fed into the work using a gravity-fed hopper, or in pressurized flow through a dedicated flux line. A suction chamber feeds any unfused flux back into the hopper so it can be reused – an efficiency which is reflected in SAW’s economics.<\/p>\n

    Travel carriage: the welding head moves, over a stationary workpiece on a gantry, or side-beam, or a workpiece moves, while the welding head stays put on a roller bed, head-tails positioner. For long structural work, the gantry-mounted SAW workstation easily covers 5 meters, and rides on a 12 meter+ track, decoupling the weld from crane movement.<\/p>\n

    Which Wire Diameter and Amperage for Which Plate Thickness?<\/h3>\n

    Wire classifications under AWS A5.17\/A5.17M<\/a> for carbon steels and AWS A5.23 for low-alloyes steels. The wire’s chemistry is specified with the classification (e.g., EM12K); this, combined with the type of flux used (e.g., F7A2) gives a prediction of the weld-metal’s mechanical properties<\/p>\n

    \n\n\n\n\n\n\n\n\n\n
    Wire Diameter<\/th>\nTypical Amperage<\/th>\nRecommended Plate Thickness<\/th>\n<\/tr>\n<\/thead>\n
    1.6 mm (1\/16″)<\/td>\n150 \u2013 350 A<\/td>\n3 \u2013 12 mm sheet, root passes<\/td>\n<\/tr>\n
    2.4 \u2013 3.2 mm (3\/32″ \u2013 1\/8″)<\/td>\n250 \u2013 600 A<\/td>\n10 \u2013 25 mm structural plate<\/td>\n<\/tr>\n
    4.0 mm (5\/32″)<\/td>\n400 \u2013 800 A<\/td>\n20 \u2013 50 mm hull plate, beams<\/td>\n<\/tr>\n
    4.8 mm (3\/16″)<\/td>\n500 \u2013 1,100 A<\/td>\n30 \u2013 80 mm pressure-vessel plate<\/td>\n<\/tr>\n
    6.4 mm (1\/4″)<\/td>\n650 \u2013 1,350 A<\/td>\n50 \u2013 250 mm thick section, multi-pass<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

    Flux choice: the fluxes are categorized by manufacturing process (fused, bonded or mechanically mixed); and by chemistry (active, neutral, alloy). Active fluxes add Si and Mn to the wire’s chemistry to produce the desired weld metal dilution; neutral fluxes don’t affect the welding wire’s mechanical chemistry, and alloy fluxes add specifier-selected levels of alloying elements to the weld metal than the welding wire carries. Fine-flux particles match fine wires and thin work; coarse particles handle the high-current, high-plate process.<\/p>\n

    Why SAW Wins on Heavy Plate (Advantages)<\/h2>\n

    \"Why<\/p>\n

    Choosing any heavy-plate fabrication shop in the world and you will see SAW running the longest seam. Here’s why: we rely on what is called the 5 kg\/h versus 45 kg\/h Threshold- the gap between the maximum manual stick welding deposition rate and the ceiling for SAW multi-arc configurations. That 9 ratio is what pays the equipment, the flux handling overhead and the joint tracking complexity it demands.<\/p>\n

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    \u2714 Advantages<\/strong><\/p>\n