Product Overview — Lincoln SuperArc L-56 ER70S-6 MIG Welding Wire
SuperArc® L-56® is Lincoln Electric's flagship copper-coated mild-steel MIG wire, classified AWS A5.18 ER70S-6. Formulated with elevated manganese (1.40–1.85%) and silicon (0.80–1.15%) deoxidizer levels, L-56 produces clean, porosity-free welds on base metals with light-to-heavy mill scale — conditions that challenge lower-deoxidizer ER70S-3 or ER70S-2 wires. The copper coating extends contact tip life and promotes consistent wire feeding over long runs. WeldingMart is an authorized Lincoln Electric distributor; every spool ships factory-fresh with full manufacturer warranty.
L-56 is available across seven diameters (.025", .030", .035", .040", .045", .052", 1/16") and more than 20 package formats, from 2 lb hobby spools to 1,000 lb Accu-Pak® boxes for robotic cells. Buy America-compliant and nuclear-grade options are available for government and power-generation procurement. Browse all sizes: Welding Wire Collection.
Specifications
| AWS Classification | AWS A5.18 / A5.18M ER70S-6 |
|---|---|
| Wire Type | Solid, Copper-Coated |
| Base Metal | Mild and low-alloy carbon steel (A36, A572, A588, etc.) |
| Available Diameters | .025", .030", .035", .040", .045", .052", 1/16" |
| Spool / Package Sizes | 2 lb, 10 lb, 12.5 lb, 33 lb, 44 lb spools; 60 lb coil; 250 lb, 500 lb, 1,000 lb Accu-Pak® drums |
| Shielding Gas | 100% CO₂ — or 75–95% Ar / balance CO₂ — or 95–98% Ar / balance O₂; flow 30–50 CFH |
| Polarity | DCEP (DC Electrode Positive / DC+) |
| Weld Process | GMAW (MIG); SAW (select sizes) |
| Transfer Modes | Short-circuit, globular, axial spray, pulsed spray |
| Tensile Strength (typical) | 530–600 MPa (77–87 ksi) as-welded with C25 gas |
| Yield Strength (typical) | 430–490 MPa (62–71 ksi) |
| Elongation (typical) | 23–25% |
| Charpy V-Notch | ≥27 J (20 ft·lbf) at −29°C (−20°F) |
| Key Conformances | AWS A5.18 ER70S-6, ASME SFA-A5.18, ABS 3YSA H5, DNV III YMS H5, MIL-70S-6 |
Source: Lincoln Electric SuperArc L-56 product page
Applications and Industries
- Structural steel fabrication: L-56 is widely specified for AWS D1.1 structural weldments on A36 and A572 steel. High deoxidizer content handles surface scale common on structural shapes without porosity.
- Automotive and body-shop repair: The .025" and .030" diameters run at low heat input, making L-56 the go-to wire for thin-gauge panels and frames on collision repair work.
- General fabrication and job shops: Excellent toe-wetting and smooth bead appearance reduce post-weld cleanup on brackets, frames, tanks, and general mild-steel weldments.
- Agricultural and heavy equipment: L-56 tolerates the lightly rusty, mill-scaled plate common on farm equipment and construction machinery without porosity or weld-quality penalties.
- Pipeline root passes (STT): Used with Lincoln's STT II process for open-root pipe welds on pipelines with minimum tensile up to 588 N/mm².
- Shipbuilding and marine fabrication: ABS and DNV / GL approvals support classification society requirements for hull plate and stiffener welding.
Polarity and Shielding Gas Requirements
SuperArc L-56 requires DCEP (DC+) polarity. Reverse the polarity leads at the machine if switching from gasless flux-cored wire (DCEN) to L-56.
Gas selection trade-offs:
- 100% CO₂: Deepest penetration profile, lowest gas cost, acceptable bead appearance. More spatter than argon mixes. Best for structural work where cleaning time is acceptable.
- 75% Ar / 25% CO₂ (C25): The most popular choice. Smoother arc, significantly less spatter, flatter bead profile. Reduce voltage 1–2 V versus CO₂ settings when using short-circuit transfer.
- 90% Ar / 10% CO₂ (C10): Optimized for spray and pulsed spray transfer at higher amperages. Lowest spatter in spray mode. Preferred for robotic cells.
- 95–98% Ar / 2% O₂: Spray and pulsed spray only — produces very flat bead profile and is used in high-production flat and horizontal applications.
Wire Diameter Selection Guide
| .025" (0.6 mm) | Auto body, thin-gauge sheet (20–16 ga). Lowest heat input. Requires a precise machine capable of very slow wire feed speeds. |
|---|---|
| .030" (0.8 mm) | Sheet metal to 3/16" plate. Best all-around hobbyist and light-fab diameter. Works on most 110V and 140–175A machines. |
| .035" (0.9 mm) | Most popular diameter. 3/16" to 1/2" plate. Versatile across all transfer modes. Runs on 180–250A machines. Part number ED028676 (12.5 lb spool). |
| .040" (1.0 mm) | Specialty size for high-deposition flat/horizontal work where .035" undershoots and .045" is oversized for the machine. Less common. |
| .045" (1.1 mm) | Heavy fabrication 3/8" and thicker. Production welding at 200–400A. Higher deposition than .035"; requires a dedicated industrial feeder. |
| .052" (1.3 mm) | High-deposition production welding and robotic applications on heavy plate. Requires spray or pulsed spray transfer. |
| 1/16" (1.6 mm) | Submerged-arc (SAW) and high-deposition robotic cells. Not used in conventional MIG guns without heavy-duty feeder infrastructure. |
Frequently Asked Questions
- What is ER70S-6 and what does it mean?
- ER70S-6 is the AWS A5.18 classification for SuperArc L-56. "E" = electrode, "R" = rod (can also be used as TIG filler), "70" = minimum 70,000 psi tensile strength, "S" = solid wire, "6" = S6 chemistry — the highest manganese and silicon deoxidizer level in the ER70S family. The S6 deoxidizer level is what allows L-56 to weld cleanly on mill-scaled or lightly rusty steel.
- What shielding gas should I use with SuperArc L-56?
- 75% Ar / 25% CO₂ (C25) is the most common choice — smooth arc, low spatter, clean bead. 100% CO₂ gives deeper penetration at lower gas cost but produces more spatter. For spray transfer at higher amperages, use 90% Ar / 10% CO₂. L-56 is NOT self-shielded and requires external shielding gas — running it without gas will cause immediate porosity.
- What is the difference between SuperArc L-56 and Harris ER70S-6?
- Both meet AWS ER70S-6 chemistry and mechanical requirements. L-56 is manufactured under Lincoln Electric's specific copper coating thickness tolerances and feedability standards. Performance differences between compliant ER70S-6 wires are subtle; choice often comes down to distributor preference and pricing.
- Can I use L-56 on rusty or dirty steel?
- Yes — the S6 deoxidizer package scavenges oxygen from mill scale, light rust, and surface oxides. It is not a substitute for proper joint prep on heavily corroded or painted steel, but it tolerates typical structural mill scale far better than ER70S-3 or ER70S-2 wires.
- What polarity does SuperArc L-56 use?
- DCEP (DC Electrode Positive / DC+). If switching from self-shielded flux-cored wire (DCEN / DC−), reverse the polarity connections before loading L-56.
- What size spool fits my welder?
- Portable 110V machines: 2 lb (4-inch) or 10 lb spools. Hobbyist 140–175A machines: 10 lb. Intermediate 180–250A machines: 10 lb or 12.5 lb. Industrial feeders: 33 lb, 44 lb, 60 lb coils. Robotic / production: 250–1,000 lb drums. Check your machine's arbor hole diameter (typically 2 inches).
Browse sibling wire PDPs: SuperArc L-56 .035" 12.5 lb Spool (ED028676) | SuperArc LA-90 .045" 44 lb (EDS30776) | All Welding Wire
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