Technical Specification · Free Download

ER70S-6 MIG Welding Solid Wire

Comprehensive technical specification for ER70S-6 MIG welding solid wire, including chemical composition, mechanical properties, standard Canadian spool sizes, feedability, common defects, and storage guidelines for fabrication shops.

Material Overview & Common Uses

ER70S-6 is a copper-coated, solid carbon steel filler wire for Gas Metal Arc Welding (GMAW) of mild and low-alloy steels. It is the most widely used MIG wire in Canadian fabrication shops due to its excellent arc stability, low spatter, and high deposition rates. The added deoxidizers (manganese and silicon) allow welding over light rust, mill scale, and surface contaminants, making it ideal for structural steel, automotive repair, farm equipment, and general fabrication. It meets AWS A5.18 ER70S-6 and CSA W48-18 requirements. Typical applications include welding A36, A572 Gr 50, and 1018 steel in thicknesses from 24 ga to 1 in. Common shielding gases are 75% Ar / 25% CO₂ (C25) or 100% CO₂ for deeper penetration.

Core Technical Properties & Sizing

Property	Specification
Chemical Composition (wt%)	C 0.06–0.15, Mn 1.40–1.85, Si 0.80–1.15, P ≤0.025, S ≤0.035, Cu (coating) ≤0.50
Mechanical Properties (as-welded, C25 gas)	Tensile Strength ≥480 MPa (70 ksi), Yield Strength ≥400 MPa (58 ksi), Elongation in 2 in ≥22%, CVN Impact 27 J @ –20°C
Standard Canadian Spool Sizes	4 in (0.5 kg, 1 lb) hobby/repair · 8 in (4.5 kg, 10 lb) portable · 12 in (11.3 kg, 25 lb) shop · 14 in (22.7 kg, 50 lb) production · 30 in (250 kg, 550 lb) bulk drums
Wire Diameters	0.023 in (0.6 mm), 0.030 in (0.8 mm), 0.035 in (0.9 mm), 0.045 in (1.1 mm), 0.052 in (1.3 mm), 1/16 in (1.6 mm). Most common in Canadian shops: 0.035 in for general fabrication, 0.045 in for heavy plate
Copper Coating	Nominal thickness 0.2–0.4 µm — provides electrical conductivity, corrosion resistance, and reduces feed friction. Coating must be uniform; bare spots cause erratic arc and increased contact tip wear
Cast & Helix	Cast (diameter of free loop) typically 15–50 in (380–1270 mm). Helix (vertical rise) ≤1 in (25 mm) per 5 ft (1.5 m) of wire. Tight cast or excessive helix causes poor feeding and birdnesting
Wire Tensile Strength	760–900 MPa (110–130 ksi) to withstand feeding forces without buckling

Machinability, Tooling & Feeds

Parameter	Recommendation
Drive Roll Type	U-groove or V-groove with knurled surface for 0.035 in and larger; smooth V-groove for 0.023–0.030 in to avoid deformation
Recommended Feed Speeds	0.035 in: 200–400 ipm for 1/8 in steel · 0.045 in: 150–300 ipm for 1/4 in steel
Contact Tip Clearance	Match tip to wire diameter (e.g., 0.035 in tip for 0.035 in wire) with 0.005–0.010 in clearance. Excessive tip wear indicates poor alignment or copper flaking
Liner Selection	For aluminum or stainless steel liners use Teflon or nylon liners to reduce friction
Cold Shop Protocol (below 10°C)	Preheat wire spool to 15–20°C to prevent moisture condensation on copper coating, which causes erratic feeding and porosity
Anti-Spatter Application	Apply to nozzle and contact tip every 10–15 minutes of arc time
Bulk Drum Unwind Tension	≤2 lb (0.9 kg) to prevent tangling

Common Defects & Quality Control

Defect	Cause	Solution
Birdnesting	Excessive tension, worn liner, or tight cast	Reduce drive roll pressure (just enough to feed without slipping); inspect and replace liner if worn
Porosity	Moisture in gas line, low gas flow (<20 cfh), or contaminated base metal	Verify gas flow 25–35 cfh and use dry gas; clean base metal
Spatter	High voltage, low wire feed speed, or wrong gas mix	Reduce voltage 1–2 V or increase wire feed speed 10%
Burnback	Slow feed speed or high inductance	Increase feed speed or reduce inductance setting
Copper Flaking	Copper coating peeling inside liner	Replace wire if flaking is visible; clean liner with compressed air
Hard Spots	Localized hard zones from improper annealing	Reject spools with inconsistent drawability; inspect incoming wire
Inconsistent Cast	Wire manufacturing variation	Feed 12 in of wire free; if loop diameter varies >10% from nominal, replace spool
Rust on Wire	Poor storage conditions	Do not use — rust causes porosity and reduced mechanical properties

Storage, Handling & Racking Guidelines

Guideline	Specification
Storage Environment	Clean, dry area at 15–25°C with ≤60% relative humidity
Packaging	Keep spools in original sealed plastic bag until use. Once opened, reseal bag or store in heated cabinet (30–40°C) to prevent moisture absorption
Contaminant Avoidance	Do not store near grinding operations or chemical fumes (acids, solvents) that can corrode copper coating
Bulk Drum Setup	Use a dedicated wire payoff station with controlled tension and a dust cover
Racking & Labeling	Rack spools on horizontal pegs or in bins with clear labeling of diameter and lot number
FIFO Rotation	Implement first-in, first-out rotation. Shelf life: 2 years unopened, 6 months after opening in humid environments
Incoming Inspection	Inspect for damaged spools, bent flanges, or crushed packaging. Reject any spool with visible rust, heavy copper flaking, or deformed wire
Winter Shipping Acclimation	Allow wire to acclimate to shop temperature for 24 hours before use to avoid condensation