ER70S-6 Vs. ER70S-G Welding Wires

What do the "6" and "G" designations mean in ER70S-6 and ER70S-G?

Both **ER70S-6** and **ER70S-G** are solid wires (indicated by the "S") with a minimum tensile strength of 70,000 psi (indicated by the "70"). The distinguishing factor lies in the final letter/number:    
   The "**6**" in ER70S-6 is a specific AWS (American Welding Society) classification that denotes a particular chemical composition, notably higher levels of **manganese and silicon**. These elements act as powerful **deoxidizers**, making ER70S-6 highly effective on materials with mill scale, rust, or other surface contaminants.    
   The "**G**" in ER70S-G stands for "General" or "Gas." It's a more generic classification, meaning that the wire's exact chemical composition, shielding gas requirements, and operating characteristics are **not as strictly specified** by AWS as with other classifications. Manufacturers often use ER70S-G for wires that meet specific application needs but don't neatly fit into other established classifications, potentially featuring unique deoxidizer combinations or lacking the traditional copper coating.

How do their chemical compositions differ, particularly in terms of deoxidizers?

**ER70S-6** has a well-defined chemical composition with guaranteed minimum and maximum percentages of key elements, especially **manganese (Mn)** and **silicon (Si)**. These higher levels of deoxidizers are engineered to clean the weld puddle effectively, reducing porosity and ensuring sound welds even on less-than-perfect surfaces.    
   **ER70S-G**, on the other hand, allows for a broader range of chemical compositions. While it will still contain deoxidizers necessary for effective **MIG welding** of **mild steel** and **carbon steel**, the specific levels of Mn, Si, and potentially other minor elements (like titanium) can vary more significantly between different manufacturers. This flexibility allows manufacturers to tailor the wire for particular performance characteristics or cost efficiencies.

What are the implications for shielding gas and arc performance?

What shielding gas is typically used with ER70S-6?

**ER70S-6** is highly versatile regarding shielding gas, performing excellently with **100% CO2** or **argon-CO2 mixtures** (e.g., 75% Argon / 25% CO2). The higher deoxidizer content helps manage the reactive nature of CO2, providing good arc stability and puddle control across different gas blends.

What shielding gas is typical for ER70S-G?

For **ER70S-G**, the specific shielding gas recommendations can vary. While many **ER70S-G** wires are designed for use with **100% CO2** or argon-CO2 mixes, it's crucial to consult the manufacturer's data sheet for the precise recommendations. Due to its "general" classification, an ER70S-G wire might be optimized for a specific gas blend to achieve its best **weld quality** and **arc stability**.

Are there differences in their typical applications?

**ER70S-6** is a workhorse in **general fabrication**, **structural steel** welding, automotive repair, and other applications where you might encounter light mill scale, rust, or oils on the base metal. Its robust deoxidizing power makes it very forgiving and widely adopted.    
   **ER70S-G** is used in a broad spectrum of applications, similar to ER70S-6, including **mild steel** and **carbon steel** welding. However, specific formulations under the "G" classification might be designed for niche applications, such as welding galvanized steel with reduced porosity, or offering a non-copper coating for specific process requirements. It’s often chosen when a manufacturer wants to offer a wire that performs well for common fabrication but has a slightly different chemical makeup or surface treatment than the more prescriptive "S-6" wire.

Does the "G" designation imply lower quality?

No, the "G" designation does not inherently imply lower quality. It simply means that the wire's detailed chemical composition and welding characteristics are not as rigidly specified by a standard AWS number (like -2, -3, or -6). A reputable manufacturer producing an **ER70S-G** wire will ensure it meets specific performance criteria for its intended use, often providing detailed product specifications. The choice between ER70S-6 and ER70S-G should always be based on the specific welding requirements and the manufacturer's detailed product data sheet.