ESAB Autrod 12.51 MIG Wire

ESAB AUTROD 12.51 MIG wire: the mild steel solid wire for MIG/MAG welding

The ESAB AUTROD 12.51 MIG wire is a mild steel solid wire designed for MIG/MAG welding on non-alloy and low-alloy steels. It ensures a stable arc, low spatter, and clean welds.

Manufactured by ESAB, a global leader in welding, this wire meets the requirements of industrial applications as well as maintenance tasks.

Available at Dagobert Industrie, it fits your standard spools for immediate implementation.

Presentation of the ESAB AUTROD 12.51 MIG wire

The ESAB AUTROD 12.51 is a mild steel solid wire designed for MIG/MAG welding. It is intended for common applications on non-alloy and low-alloy steels, both in the workshop and on-site.

This wire is manufactured by ESAB, one of the world leaders in welding. It benefits from a meticulously copper-coated surface that ensures smooth feeding and good electrical conductivity at the contact tip.

Result: a stable arc, low spatter, and clean beads even at high speeds.

Composition and normative classification

AUTROD 12.51 is classified as G3Si1 according to EN ISO 14341-A, which corresponds to the ER70S-6 designation according to AWS A5.18. This is the reference classification for mild steel MIG wires.

Its composition includes high levels of silicon (Si) and manganese (Mn), which act as powerful deoxidizers. This allows welding of slightly rusted or mill-scaled steels without compromising the quality of the joint.

The recommended shielding gases are Ar/CO₂ mixtures (typically M21) or pure CO₂. The choice of gas directly influences penetration and bead appearance.

Wire	Classification EN ISO 14341-A	Equivalent AWS	Si Content	Typical Usage
ESAB AUTROD 12.51	G3Si1	ER70S-6	~0.90 %	Mild steel, imperfect surfaces
ESAB AUTROD 12.10	G2Si1	ER70S-3	~0.65 %	Mild steel, clean surfaces
Lincoln Electric SuperArc L-56	G3Si1	ER70S-6	~0.85 %	Mild steel, imperfect surfaces
Böhler EMK 6	G3Si1	ER70S-6	~0.90 %	Mild steel, general purpose

Technical characteristics and mechanical properties of the AUTROD 12.51 wire

The ESAB AUTROD 12.51 is a mild steel solid wire designed for MIG/MAG welding under shielding gas. Its chemical composition is carefully controlled to ensure regular beads and excellent mechanical strength.

It is manufactured in accordance with EN ISO 14341-A (G 42 2 C/M G2Si1) and AWS A5.18 (ER70S-3) standards. These classifications ensure broad compatibility with common structural steels.

The wire is available in standard diameters: 0.8 mm, 1.0 mm, and 1.2 mm. Each diameter covers different sheet thicknesses and welding intensities.

Mechanical properties of the deposited metal (typical values):

• Tensile strength: ≥ 500 MPa
• Yield strength: ≥ 420 MPa
• Elongation at break: ≥ 22 %
• Impact toughness KV at -20 °C: ≥ 47 J

The copper coating on the wire limits contact resistance and reduces contact tip wear. Feeding is smooth, even at high speeds.

Product	Standard	Recommended Gas	Si Content	Typical Usage
ESAB AUTROD 12.51	G 42 2 C/M G2Si1 / ER70S-3	Pure CO₂ or Ar/CO₂	~0.65 %	Mild steel, general construction
ESAB AUTROD 12.64	G 46 4 M G3Si1 / ER70S-6	Ar/CO₂ (M21)	~0.85 %	Slightly oxidized mild steel, less clean surfaces
Lincoln Electric SuperArc L-56	ER70S-6	Ar/CO₂ (M21)	~0.85 %	Mild steel, oxidized or rusted surfaces
Böhler EMK 6	G 42 4 M G3Si1 / ER70S-6	Ar/CO₂ (M21)	~0.80 %	Mild steel, all-position semi-auto welding

The AUTROD 12.51 stands out for its moderate silicon content. It is perfectly suited for clean and well-prepared steels, where an ER70S-6 wire might provide more slag than necessary.

Fields of application: which materials and processes are compatible?

The ESAB AUTROD 12.51 MIG wire is designed for MIG/MAG welding of non-alloy and low-alloy steels. It is perfectly suited for common mild steels, in particular grades S235, S275, and S355.

This solid wire can be used both with direct current reverse polarity (DC+) and with conventional shielding gases. It is compatible with Ar/CO₂ mixtures (typically 82/18 or 75/25) as well as pure CO₂.

Sectors that use it daily:

• Boilermaking and light to heavy steel construction
• Fabrication of welded structures and frames
• Automotive industry and bodywork
• Industrial maintenance and repair
• Low-pressure steel piping

Recommended welding parameters

Settings vary according to the wire diameter used. Here are the common ranges for the most popular diameters:

Diameter (mm)	Current (A)	Voltage (V)	Recommended Gas	Welding Position
0.8	60-180	16-22	Ar/CO₂ or pure CO₂	All positions
1.0	80-250	17-26	Ar/CO₂ or pure CO₂	All positions
1.2	120-350	19-30	Ar/CO₂ or pure CO₂	PA, PB, PC
1.6	200-500	22-34	Ar/CO₂ or pure CO₂	PA, PB

In 1.2 mm diameter with an Ar/CO₂ mixture, the AUTROD 12.51 offers a very stable arc and excellent spray transfer at high intensity. This is the preferred setting for filling passes on thick plates.

For work in difficult positions (vertical up, overhead), prefer the 0.8 or 1.0 mm diameter with short-circuiting mode to control the weld pool.

Comparison: ESAB AUTROD 12.51 versus other mild steel MIG wires on the market

The market for mild steel MIG wires is broad. To help clarify, here is how the ESAB AUTROD 12.51 compares to the most well-known references.

The 12.51 is an ER70S-6 solid wire, the most popular for MIG/MAG welding on non-alloy steels. Its high manganese and silicon content gives it an advantage on slightly oxidized or greasy surfaces, where other wires fail.

Product	Manufacturer	Classification	Si/Mn Content	Strength	Typical Usage
AUTROD 12.51	ESAB	ER70S-6 / G3Si1	High	Excellent tolerance to imperfect surfaces, stable arc	Steel construction, light boilermaking
AUTROD 12.22	ESAB	ER70S-3 / G2Si	Moderate	Less slag, welding on clean steel	Pickled steels, clean surfaces
Filarc PZ6500	ESAB	ER70S-6	High	Optimized for high-speed robotic welding	Automotive industry, mass production
Marathon Pac 12.51	ESAB	ER70S-6 / G3Si1	High	Same filler metal, giant spool packaging for robots	Automated welding, continuous production
Lincoln SuperArc L-56	Lincoln Electric	ER70S-6	High	Soft arc, good penetration	Repair, general fabrication
Böhler EMK 6	Voestalpine Böhler	ER70S-6 / G3Si1	High	Very low spatter level	Fine boilermaking, visible welding

Compared to its direct competitors in ER70S-6, the AUTROD 12.51 is distinguished by the consistency of its manufacturing quality and the regularity of its diameter from wire to wire, a crucial point for arc stability in production.

Compared to the AUTROD 12.22 (G2Si), the 12.51 better tolerates less well-prepared steels. If your surface is clean and pickled, the 12.22 generates less slag. For everything else, the 12.51 is the default choice.

Usage tips and best practices to optimize your welds

The ESAB AUTROD 12.51 MIG wire gives its best performance when machine settings and part preparation are carefully managed. Here are the key points to respect.

Prepare your parts before welding. Degrease and pickle the surfaces to be joined. Oxides, rust, or oil residues degrade bead quality and generate porosity.

Use an appropriate shielding gas: an Ar/CO₂ (80/20) mixture is suitable for most mild steel applications. Pure CO₂ remains an economical option but produces more spatter.

Set the gas flow between 12 and 18 L/min. Flow that is too low exposes the weld pool to ambient air; flow that is too high creates turbulence and impairs protection.

Adapt the wire feed speed and intensity to the part's thickness. On thin sheets (1 to 2 mm), reduce the voltage to avoid burn-through. On thicknesses greater than 6 mm, favor multiple passes.

Maintain a torch angle between 10° and 15° relative to the vertical and a regular contact-tip-to-work distance (stick-out of 10 to 15 mm). This stabilizes the arc and improves penetration.

Regularly clean the wire liner and check the condition of the drive rolls. Poorly guided wire causes arc stuttering and fusion defects.

FAQ - ESAB AUTROD 12.51 MIG WIRE

1. What types of steel is the ESAB AUTROD 12.51 wire suitable for?

The AUTROD 12.51 is designed to weld mild steels and non-alloy structural steels.

It is perfectly suited for S235, S275, and S355 type steels, which are very common in boilermaking, metalworking, and mechanical construction.

2. Which shielding gas should be used with this MIG wire?

The AUTROD 12.51 works with an Ar/CO₂ mixture (typically M21: 80% argon / 20% CO₂).

Pure CO₂ (C1) can also be used. It provides deeper penetration but generates more spatter.

For a clean weld with little spatter, the Ar/CO₂ mixture remains the best option.

3. What is the difference between the AUTROD 12.51 and the AUTROD 12.10?

The AUTROD 12.10 is a basic, economical wire for common applications without high mechanical requirements.

The AUTROD 12.51 offers a higher manganese and silicon content, which improves the mechanical strength of the deposit and the quality of the weld pool.

For mechanically loaded assemblies, the AUTROD 12.51 is clearly the better choice.

4. Is this wire suitable for welding in all positions?

Yes. The AUTROD 12.51 can be used in all welding positions (PA, PB, PC, PF…).

Its pool fluidity and good deoxidation make it easier to work in vertical up or overhead positions.

5. Which standard covers the AUTROD 12.51?

This wire is classified according to standard EN ISO 14341: G 42 4 M21 3Si1.

It also meets the AWS A5.18 classification: ER70S-6, an international reference widely used to validate welding procedures (WPS/PQR).

6. Can the AUTROD 12.51 be used on slightly oxidized or rusted parts?

The AUTROD 12.51 contains sufficient deoxidizers (Si + Mn) to tolerate imperfect surface conditions.

However, it is still recommended to brush and degrease the parts before welding to ensure the mechanical quality of the joint.

For heavily degraded surfaces, prior pickling is required regardless of wire quality.