Lincoln Electric SuperArc® L-59® is a copper-coated, engineered-alloy MIG wire classified per AWS A5.18/A5.18M: ER70S-6 that leads Lincoln Electric's premium MIG wire lineup for carbon steel GMAW. Unlike standard ER70S-6 wires, L-59 incorporates Lincoln's MicroGuard® Ultra surface treatment and a proprietary engineered alloy system that manages silicon island formation at the weld surface — the oxides that accumulate on the bead face and require manual chipping before multi-pass welding or painting. The result is a wire that delivers faster travel speeds, minimum spatter, and exceptional contact tip longevity in high-duty-cycle production environments. Conformances include ABS 3YSA (100 % CO₂ and mixed gas), Bureau Veritas III YMS H5 (mixed gas), and CWB/CSA W48 ER49S-6.
| Parameter | Value |
|---|---|
| AWS Classification | ER70S-6 (AWS A5.18/A5.18M: 2005 / ASME SFA-A5.18) |
| Additional Conformances | ABS 3YSA (CO₂ + mixed); BV III YMS H5 (mixed); CWB ER49S-6 |
| Available Diameter (this SKU) | 0.035 in (0.9 mm) |
| Package (this SKU) | 33 lb (15 kg) fiber spool |
| Surface Treatment | MicroGuard® Ultra copper coating |
| Shielding Gas | 75% Ar / 25% CO₂ preferred; 100% CO₂ acceptable |
| Polarity | DCEP (DC electrode positive) |
| Tensile Strength (as-welded) | 485 MPa (70 ksi) minimum; typical 538–586 MPa (78–85 ksi) |
| Yield Strength (as-welded) | 400 MPa (58 ksi) minimum |
| Elongation | 22 % minimum; typical 26–30 % |
| Charpy V-Notch Impact | 27 J (20 ft-lbf) at −29 °C (−20 °F) |
SuperArc L-59's combination of premium feedability, silicon island management, and extended contact tip life makes it the preferred ER70S-6 variant for high-production environments where consumable costs and downtime are critical metrics:
- Automotive and tier-1 supplier fabrication — robotic and semi-automatic welding of chassis components, cross-members, and structural stampings where tip replacement frequency directly impacts line throughput
- Structural steel fabrication (shop) — beam fabrication lines, connection plate welding, and bracket subassembly where fast travel speeds and clean bead appearance are required
- Pressure vessel and boiler manufacturing — seam and nozzle welding on A516/A537 plate where ABS or BV mill conformances are required for marine and offshore classification
- OEM equipment manufacturing — production welding of forklifts, agricultural machinery, material handlers, and construction equipment frames
- General fabrication with robotic automation — any application where wire feedability consistency and arc stability are essential to avoid robotic cell stoppages
Standard ER70S-6 wires leave silicon oxide islands on the weld bead surface that must be removed before applying additional passes or paint. L-59's engineered alloy system redistributes the silicon-manganese oxide reaction products so they form smaller, more dispersed islands that are easier to remove — reducing inter-pass cleanup time and improving paint adhesion on finished welds. The MicroGuard® Ultra copper coating provides uniform, thin copper coverage that maximizes electrical conductivity and reduces copper flaking in the liner and contact tip, directly extending tip service life in high-duty-cycle operations.
Per Lincoln Electric's SuperArc L-59 product page, this wire is recommended for applications requiring the combination of AWS A5.18 ER70S-6 mechanical properties and premium process performance. For 0.035 in wire with 75/25 Ar/CO₂ gas, typical operating range is 80–175 amps at 16–22 V, covering short-circuit through lower globular transfer.
| Diameter | Polarity | Gas | Voltage (V) | Current (A, approx.) | Transfer Mode |
|---|---|---|---|---|---|
| 0.035 in (0.9 mm) | DCEP | 75/25 Ar/CO₂ | 16–19 | 80–130 | Short-circuit |
| 0.035 in (0.9 mm) | DCEP | 75/25 Ar/CO₂ | 19–22 | 130–175 | Globular transition |
| 0.035 in (0.9 mm) | DCEP | 100% CO₂ | 17–21 | 85–150 | Short-circuit |
SuperArc L-59 meets the same AWS A5.18 ER70S-6 classification as commodity ER70S-6 wire but adds Lincoln Electric's MicroGuard® Ultra surface treatment and an engineered alloy system designed to reduce silicon island formation on the weld bead face. The practical result is longer contact tip life, better feedability in high-duty-cycle operations, faster travel speeds, and improved inter-pass paint adhesion compared to standard ER70S-6.
MicroGuard® Ultra is Lincoln Electric's proprietary copper surface treatment applied to SuperArc wires. It provides a thinner, more uniform copper layer than conventional heavy copper coatings, which reduces copper flaking inside wire liners and contact tips. Less flaking means fewer tip plugging events, longer tip life, and more consistent arc stability — particularly important in robotic and automated GMAW cells where tip changeover causes production stoppages.
SuperArc L-59 is classified as ER70S-6 per AWS A5.18/A5.18M: 2005 and ASME SFA-A5.18. Additional conformances include ABS 3YSA for marine applications (both CO₂ and mixed gas), Bureau Veritas III YMS H5 (mixed gas), and CWB/CSA W48 ER49S-6 for Canadian Welding Bureau requirements.
The preferred shielding gas is 75 % Argon / 25 % CO₂, which produces the lowest spatter, flattest bead profile, and best silicon island management. 100 % CO₂ is also compatible and reduces gas cost, but produces more spatter, a more convex bead, and slightly higher silicon island formation. Avoid high-argon blends above 90 % Ar with ER70S-6, as the spray transfer regime becomes active at lower currents and may not be compatible with thinner material applications.
Yes. SuperArc L-59 holds ABS 3YSA classification for American Bureau of Shipping requirements and Bureau Veritas III YMS H5 for BV-classed marine structures. These approvals make it suitable for ship hull, offshore platform, and marine infrastructure applications where classification society approval of welding consumables is mandatory.
Browse the full welding wire collection, or compare to SuperArc L-56 for the standard copper-coated MIG wire option, or Harris ER70S-6 for a value-priced ER70S-6 alternative.