AWS A5.18 / ASME SFA-5.18 · Solid MIG wire & TIG rod (GMAW / GTAW)

ER70S-3 MIG Wire and TIG Rod

ER70S-3 is a manganese-silicon deoxidised solid wire classified to AWS A5.18 for gas metal arc and gas tungsten arc welding of carbon and carbon-manganese steels, depositing weld metal with a minimum tensile strength of 70,000 psi (490 MPa) and carrying less manganese and silicon than ER70S-6 — which gives a flatter bead on clean prepared plate but less tolerance of mill scale, rust and surface contamination.

Carbon and carbon-manganese steel, clean prepared plate
Solid MIG wire & TIG rod (GMAW / GTAW)
EN ISO 14341-A / EN ISO 636-A
3 ESAB grades

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Price on request. POFIS is an ESAB Authorized Distributor & Service Centre in Abu Dhabi — quotations include confirmed lead time and delivery terms.

The designation

What ER70S-3 means

ER: An electrode or rod — the same filler fed as continuous MIG wire or cut into lengths as TIG rod.
70: Minimum tensile strength of the deposited weld metal in thousands of pounds per square inch — 70,000 psi, which is 490 MPa. Identical to ER70S-6: the two classes are the same strength.
S: Solid wire, as opposed to a tubular flux-cored or metal-cored electrode. All shielding comes from the gas.
3: The chemistry suffix, and the only real difference from ER70S-6. A 3 means moderate manganese and silicon; a 6 means the highest of the carbon steel solid wires. Those elements are deoxidisers, so this is a direct statement about how much surface contamination the wire can cope with.
G 2Si: The EN ISO 14341-A equivalent. The 2Si against the 3Si1 or 4Si1 of an ER70S-6 wire is the same information in EN form: less silicon.

Reading the ER70S-3 designation, left to right.

How it behaves

ER70S-3 in practice

The whole difference is deoxidiser content

ER70S-3 and ER70S-6 are both 70 ksi classes with the same nominal strength. What separates them is manganese and silicon, which scavenge oxygen from the weld pool. ER70S-6 carries the most of any carbon steel solid wire, so it copes with mill scale, light rust and residual oil. ER70S-3 carries less, so on contaminated plate the oxygen it cannot scavenge ends up as porosity. That is the entire selection question, and it is about plate condition rather than about the joint.

Why ER70S-3 still exists

On genuinely clean, prepared material it gives a slightly flatter bead with less silicon residue on the surface — silicon islands have to be removed before painting or before the next pass, so less silicon means less cleaning. It is also marginally cheaper. In a controlled environment working from clean sheet or machined preparation, those are real advantages. ESAB names general structural, pressure vessel and shipbuilding steels with a minimum tensile strength of 500 MPa among its applications.

Why most buyers should take ER70S-6 anyway

Plate in a fabrication shop or on a site is rarely as clean as a procedure assumes. Mill scale, flash rust from overnight humidity and handling residue are normal rather than exceptional, especially in a Gulf climate where condensation is routine. ER70S-6 tolerates all of them. The flatter bead and lower silicon of ER70S-3 are worth having only where the preparation is reliably good — and if that cannot be guaranteed shift to shift, the more forgiving wire is the cheaper choice overall.

Gas changes the figures here too

As with every solid wire, properties depend on shielding gas. OK Autrod 12.58 gives 420 MPa yield under M21 and 400 MPa under pure CO₂, with room-temperature impact values of 125 J under CO₂. The wires are classified for both, so the choice is open — but a procedure qualified on one gas is not qualified on the other, and the gas has to match the WPS rather than whatever is on the trolley.

The TIG rod is a different proposition

OK Tigrod 12.60 under pure argon gives 450 MPa yield and, notably, 250 J at −20 °C — far above anything the MIG wires in this class publish. TIG deposits are cleaner because the process is cleaner: no spatter, no transfer across the arc, and a shielding gas with no oxidising addition. Where a root run in clean prepared material needs toughness, an ER70S-3 TIG rod is a stronger candidate than the class as a whole might suggest.

What POFIS supplies

ESAB ER70S-3 grades

Every grade below carries the ER70S-3 classification, which is why a WPS naming ER70S-3 can be satisfied by any of them. They are not interchangeable in practice — the differences in current type, hydrogen level and impact toughness are what decide which one belongs on your job. Figures are the manufacturer's typical as-welded values.

**ER70S-3 grades supplied by POFIS** — typical as-welded properties. Blank cells are values the manufacturer does not publish for that grade, not zeros.
Grade	Classification	Yield	Tensile	Elong.	Impact (lowest published)
OK Autrod 12.58 POFIS recommends	ER70S-3 (AWS A5.18) G 2Si / G 38 3 M21 2Si (EN ISO 14341-A)	420 MPa (M21)	515 MPa (M21)	26 %	125 J at 20 °C (C1)
OK Tigrod 12.60	ER70S-3 (AWS A5.18) W 2Si (EN ISO 636-A)	450 MPa (Ar)	540 MPa (Ar)	33 %	250 J at −20 °C
OK AristoRod 12.57	ER70S-3 (AWS A5.18) G 2Si / G 38 3 M21 2Si (EN ISO 14341-A)	420 MPa (M21)	515 MPa (M21)	26 %	90 J at −30 °C

OK Autrod 12.58 ER70S-3 (AWS A5.18)

The general-purpose copper-coated wire and the widest diameter range in this class at 0.6 mm to 1.6 mm, covering thin sheet through heavier fabrication. Usable on a gas mixture or pure CO₂, and available in the octagonal Marathon Pac.

Diameters: 0.6 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.6 mm
Alloy type: Carbon-manganese steel (Mn/Si-alloyed), copper coated
Type: Solid MIG wire (GMAW), M21 or C1
Source: ESAB Filler Metal Handbook, page 1-44

OK Tigrod 12.60 ER70S-3 (AWS A5.18)

Much the toughest grade here at 250 J at −20 °C under pure argon, with 450 MPa yield. For general engineering and structural steels with a minimum yield of 380 MPa — and a strong candidate for root runs in clean prepared material.

Alloy type: Carbon-manganese steel
Type: TIG rod (GTAW), shielding I1
Source: ESAB Filler Metal Handbook, page 1-63

OK AristoRod 12.57 ER70S-3 (AWS A5.18)

The non-copper-coated version with ASC surface treatment, for robotic and mechanised runs where copper build-up in the contact tip and liner costs production. For structural, pressure vessel and shipbuilding steels to 500 MPa minimum tensile.

Diameters: 0.9 mm, 1.0 mm, 1.2 mm, 1.6 mm
Alloy type: Carbon-manganese steel (Mn/Si-bearing), non copper coated
Type: Solid MIG wire (GMAW), M21 or C1
Source: ESAB Filler Metal Handbook, page 1-34

Diameters are listed from the manufacturer's deposition data. Ordering part numbers and pack sizes are confirmed with your quotation — send the grade and diameters you need to weldiv@pofis.ae.

Specifying

Which ER70S-3 grade to specify

For MIG welding on clean prepared plate

OK Autrod 12.58 is the copper-coated general-purpose wire and the one with the widest diameter range in this class — 0.6 mm up to 1.6 mm, which covers thin sheet through to heavier fabrication. Usable on a gas mixture or pure CO₂, and available in the octagonal Marathon Pac bulk drum for mechanised work. 420 MPa yield under M21.

For robotic and mechanised runs

OK AristoRod 12.57 is the non-copper-coated equivalent with ESAB's ASC surface treatment, 0.9 mm to 1.6 mm. The absence of copper flash means less build-up in the contact tip and liner over long uninterrupted runs, which is the same argument as on the ER70S-6 page and matters for the same reason. 420 MPa yield under M21, with 110 J at −20 °C and 90 J at −30 °C.

For TIG work

OK Tigrod 12.60 is the copper-coated rod for general engineering and structural steels with a minimum yield strength of 380 MPa, shielded by pure argon. It publishes 450 MPa yield, 540 MPa tensile and 250 J at −20 °C — much the toughest figure on this page, and a reason to consider it for root runs in clean material.

If the plate condition is not reliable

Specify ER70S-6 instead. The higher manganese and silicon are what let a wire weld over mill scale and light rust without porosity, and in most real fabrication environments that tolerance is worth more than the flatter bead and marginally lower cost of ER70S-3. The ER70S-6 page covers ten ESAB grades including the pipeline and low-temperature variants.

If the work is high volume

A metal-cored wire will out-deposit a solid wire of the same diameter with a wider, more tolerant arc, and a flux-cored wire will out-deposit both while welding out of position. Where the quantity of carbon steel fabrication justifies it, those are the productivity steps — ER70S-3 is a precision choice rather than a volume one.

Storage & handling

Storing and handling ER70S-3 consumables

Surface preparation is not optional with this wire

The lower deoxidiser content is precisely a reduced tolerance for contamination. Degrease, remove mill scale and deal with flash rust before welding, and treat plate that has sat overnight in humid conditions as needing attention. A wire chosen for a clean-plate advantage gives that advantage back immediately if the plate is not clean.

Store wire dry and close the drum

Solid wire does not absorb moisture the way a basic electrode coating does, but surface rust and condensation on a part-used spool both cause porosity — and on a lower-deoxidiser wire there is less margin to absorb it. Keep spools packaged in a dry area and close a Marathon Pac between shifts rather than leaving it open to workshop air.

Frequently asked

ER70S-3 — common questions

What is the difference between ER70S-3 and ER70S-6?

Deoxidiser content, not strength — both are 70 ksi classes. ER70S-6 carries the highest manganese and silicon of the carbon steel solid wires, so it tolerates mill scale, surface rust and residual oil. ER70S-3 carries less, so on contaminated plate the oxygen it cannot scavenge becomes porosity. ER70S-3 gives a slightly flatter bead with less silicon residue on genuinely clean material.

Should I use ER70S-3 or ER70S-6?

ER70S-6 in most cases. Plate in a fabrication shop or on site is rarely as clean as a procedure assumes — mill scale and flash rust from overnight humidity are normal rather than exceptional, particularly in a Gulf climate. ER70S-3 is worth having where preparation is reliably good shift to shift, because it leaves less silicon to clean off before painting. If that cannot be guaranteed, the more forgiving wire is the cheaper choice overall.

Is ER70S-3 weaker than ER70S-6?

No. Both have the same minimum tensile strength of 70,000 psi, which is 490 MPa, and the ESAB grades in both classes publish similar yield figures. The difference is in how much surface contamination the wire can handle, not in the strength of a sound weld.

Can ER70S-3 be used with pure CO₂?

Yes — ESAB states its ER70S-3 wires can be welded with either a gas mixture or pure CO₂, and publishes figures for both. They differ: OK Autrod 12.58 gives 420 MPa yield under M21 and 400 MPa under CO₂. A procedure qualified on one gas is not qualified on the other, so match the gas to the WPS.

What is the difference between AristoRod and Autrod in this class?

The surface, not the chemistry. OK Autrod 12.58 is copper-coated in the traditional way. OK AristoRod 12.57 is non-copper-coated with ESAB's advanced surface characteristics treatment, which stops copper flaking into the contact tip and liner. On short manual runs this makes little difference; on long robotic or mechanised runs it is the difference between a continuous shift and stoppages to clear a liner.

Why does the TIG rod have much higher impact values than the MIG wires?

Because the process is cleaner. OK Tigrod 12.60 publishes 250 J at −20 °C under pure argon, against 90 to 110 J for the MIG wires. TIG has no spatter, no metal transferring across the arc and a shielding gas with no oxidising addition, so the deposit picks up less oxygen. Where a root run in clean material needs toughness, this makes the TIG rod a stronger candidate than the class as a whole suggests.

What wire diameter should I use for sheet metal?

OK Autrod 12.58 goes down to 0.6 mm, which is the smallest in this class and suited to thin sheet. As a general guide: 0.6–0.8 mm for sheet and thin section, 0.9–1.0 mm for general fabrication and positional work, 1.2 mm for most structural welding, and 1.6 mm for heavier plate. The diameter also has to suit the machine output and the feeder rolls.

Who supplies ER70S-3 MIG wire in Abu Dhabi?

POFIS supplies the ESAB OK Autrod, AristoRod and Tigrod ranges from Abu Dhabi across the UAE and the wider GCC, as an ESAB Authorized Distributor and Service Centre, approved ADNOC vendor and ISO 9001 certified supplier. Tell us the plate condition as well as the diameter and gas, and we will tell you honestly whether ER70S-3 or ER70S-6 is the better buy. Email weldiv@pofis.ae.

Procurement & supply

Buying the ER70S-3 consumables through POFIS

The ER70S-3 consumables is supplied from Abu Dhabi by Perfect Oilfield & Industrial Supply LLC as an ESAB Authorized Distributor and Service Centre. The information below covers what procurement and QA/QC departments normally need before raising a purchase order.

Lead time

Stock items dispatch from Abu Dhabi within 24–48 hours. Indent items are quoted with a confirmed lead time at the time of offer.

Approved vendor status

POFIS is an approved ADNOC vendor and is listed on the approved vendor lists (AVL) of major operators and EPC contractors across the GCC. We can complete supplier registration and prequalification documentation on request.

Payment terms

Standard credit terms are available to registered corporate accounts. LPO, LC and advance payment are all accepted.

Delivery terms

Delivery across the UAE and the wider GCC. Quotations can be issued on EXW, FOB, CIF or DDP terms to suit your project.

Warranty

Full manufacturer warranty, honoured locally. As an ESAB Authorized Service Centre we carry out warranty work and repairs in Abu Dhabi rather than returning equipment abroad.

Service & spares

In-UAE service, commissioning, operator training and spare parts backing for every machine we supply.

ISO 9001 Certified
Approved ADNOC Vendor
ESAB Authorized Distributor & Service Centre

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Request a quotation for the ER70S-3 filler metals

Send the form and the POFIS welding division replies with pricing, confirmed lead time, delivery terms and availability. Tell us who you are and what the job is, so the reply can be specific to it rather than a catalogue price list.

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