ER70S2 vs ER70S6 : Their Essence In Arc Welding

Arc welding is a common activity widely used by welders in various applications at work. These can be in the construction and repair of ships at sea, buildings, and vehicles. Moreover, in pipeliners, pipefitters, and boilermakers, this is a constant demand work activity done by welders. 

Arc welding is carried out by either experienced professionals or beginners in the field of welding thus it is important to what welding wires, electrodes, and other welding-related tools are required for the attainment of greater outcomes.

ER70S2 vs ER70S6

In Arc welding, there exists electrodes or welding rods such as 6011 and 6010 among others used in the specified applications based on their key features. More so, there exist low alloy steels that are used in MIG or TIG welding applications. 

What is low alloy steel? This is steel alloyed with several elements ranging between 1.5 % to 5%. The alloying aids in enhancing the steel’s mechanical properties for better welding. Alloy steel mainly insinuates steel coated with other alloying elements besides the carbon element in it. Examples of alloying elements include the following;







Most alloy steels are bound to have either 4 or 5 of the above-mentioned alloys in distinct amounts. In Arc welding, there are two types of wires or rods namely;

MIG wires

TIG wires

In this article, we are going to discuss how the following welding wires can be applied, their tensile strength, the available alloying elements in them among others. These rods include;



According to the American Welding Society (AWS), these MIG and TIG rods are preferably used by welders in most welding applications to the existing others. The AWS  has standardized classification criteria on how the wires are categorized using letters and numbers to help the welders in adjusting to the preferred mechanical property for use. On looking at the classification, let’s take ER70S-6 as an example. According to the AWS classification, it is AWS A5.18.

Being a standard MIG welding wire of carbon steel, the E, R, refers to the Rod or Electrode thus making it to mean a wire.

70 Is meant to give an outlook of how the post-deposited metal wire used in the welding has a minimum tensile strength of 70,000 psi (480MPa).

S-stands for an acronym of solid meaning the solid core wire in the welding process. Besides that S, there is a Standard C meaning Composite. This states the wire for metalcore.

6-shows the deposited metal wire ingredients also called components having its reference standards.

What Is ER70S-2?

This is a famously known TIG welding wire mainly used on Carbon and low alloy steels. Besides, it can also be used as a MIG welding wire in the welding process since it has key features that embody all the characteristics that each of the welding rods requires. 

Scientifically, ER70S-2 is a triple deoxidized wire mainly applied in welding carbon and Carbon-Manganese steels. In the process, the tensile strength of the wire ranges up to 73,970 psi (510MPa).  This combination reduces the outcome of weld deposits defects if used properly and precisely by the welder in various carbon steels. 

If properly used, ER70-2 wire is inevitable to attain high-quality welds especially on most grades of carbon steel. Furthermore, when two elements namely Manganese and Silicon are added in the wire, deoxidation is greatly enhanced. 

This is very crucial especially when welding on mill scale and slightly rusty metal surfaces. ER70S-2 can be applied in welding on various materials such as thin, electro-galvanized as well as galvanized surfaces thus the production of less spatter in the process.

Here area  few examples of some of the renowned base materials that can be welded using ER70S-2;

A210 Gr C

A131 Gr A, B, D



A234 Gr WPB





In Arc Welding, when using ER70S-2  the welder can comfortably use it all positions hence making it more reliable.

We have looked at what steel alloys are. It should be noted that these alloys are what sum up the Chemical composition of The Wire. Thus, what is the Chemical Composition of ER70S-2?


Definitive mechanical properties concerning as follows:

The AWS code assigned to ER70S-2 is AWS A5.18 ASME SFA 5.18.

Yield Strength at psi is 63,820 psi (440 MPa)

ER70S-2 Tensile strength is 75,420 psi (520 MPa)

The average percentage of elongation of the wire is 28%

What Is ER70S-6 Welding Wire?

This is a well known TIG wire having higher levels of Deoxidizers namely Manganese (Mn) and Silicon (Si) making it different from other related carbon steel wires. ER70S-6 is popularly called a Filler Metal due to its higher level of Silicon hence the more fluid.

This results in the ability to float oxides to the surface during the welding process. It mainly used Argon and Carbon II oxide as shielding gases with amounts of 75 and 25 respectively.



Tensile Strength – 77,000 psi.

Applies to all Welding positions.

Uses Argon and Carbon II oxide as shielding gases during welding.

The Difference In Application Between ER70S-2 and ER70S-6

ER70S-2 ( GTAW) Areas of Application

Aids in repair of different low and mild alloy steels

Used in Sheet Metal Applications

Utilized in the Root pass pipe welding process.

Suitable for small diameter pipe as well as tubing

ER70S-6 (GTAW) (TIG) Areas of Application

Used mainly on steels with dirty and rusty surfaces before cleaning for a single pass.

Used in the repair of mild and low alloy steels

Mainly used in sheet metal applications.

MIG and TIG Welding Wires

Previously, we stated two crucial words TIG and MIG. Let’s take a deep dive into the two and what they entail in-depth.

There exist specific wires made entirely for TIG welding. However, if a TIG wire is unavailable its better to use a MIG welding wire. 

Most TIG wires are available in thicker sizes compared to MIG wires. TIG wires are usually in straight form while MIG wires are curved.

TIG is Tungsten Inert gas also called Gas Tungsten Arc Welding( GTAW). The name suggests that this welding type uses a non-consumable tungsten welding rod to produce the weld an example being ER70S-2. MIG welding is Metal Inert gas in full a good example being ER70S-6.

The Difference between TIG and MIG Welding wires

TIG is commonly known as Filler wire. Previously we stated that TIG wires come in a straight manner thus it requires no straightening. This makes it less time consuming as the welder can immediately put it into use after buying.

MIG wire is curved in shape and less thick. In TIG welding a welder would preferably use a Thicker wire than a thin wire. Hence TIG rod becomes the most used welding wires.


Arc welding is easy if one uses the right tools required putting in mind the Chemical Properties, Tensile strength, Yield strength, the amount of each element in the allow, and how to apply the different welding wires.

David Ferguson

A professional and passionate welder, a writer who loves to write about the welding and plasma cutting tools. In this site, you will get all the information about welding tools in depth. Just share your feedback and suggestion that will help the website to grow more. Find me: Facebook

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