Frequently Asked Questions: Why ER70S-6 is Often Called "CO2 Wire

Why is ER70S-6 welding wire frequently referred to as "CO2 wire"?

ER70S-6 is commonly known as "CO2 wire" because it is designed to be primarily used with **100% carbon dioxide (CO2) shielding gas** in Gas Metal Arc Welding (GMAW), also widely known as **MIG welding**. While it can be used with argon/CO2 mixtures, its formulation is specifically optimized to perform exceptionally well with pure CO2, making it a highly economical and effective choice for many applications.

What are the benefits of using 100% CO2 shielding gas with ER70S-6?

Using 100% CO2 with ER70S-6 offers several advantages. CO2 is a very **cost-effective** shielding gas compared to argon or argon mixtures. It provides good **arc penetration**, which is beneficial for welding thicker sections and achieving strong, robust welds. While it may produce a slightly less stable arc and more spatter compared to argon-rich blends, the economic benefits and good mechanical properties often make it the preferred choice for **general fabrication** and **structural steel** work.

What types of welding processes and materials is ER70S-6 suitable for?

ER70S-6 is a versatile solid wire electrode used predominantly in **MIG welding (GMAW)**. It is an excellent choice for welding **mild steel** and low-alloy steels. It's suitable for various transfer modes, including **short-circuit transfer**, **spray transfer**, and **pulsed spray** (though pulse often uses gas mixtures). Its broad applicability makes it a staple in workshops for everything from automotive repairs to heavy machinery fabrication.

How does the composition of ER70S-6 contribute to its performance with CO2?

ER70S-6 contains higher levels of **manganese and silicon** as **deoxidizers** compared to other ER70S series wires. These deoxidizers are crucial when using 100% CO2 shielding gas, which is an active gas and can lead to oxidation of the weld puddle. The increased deoxidizer content helps to scavenge oxygen, preventing porosity and ensuring a clean, sound weld bead. This chemical composition is key to achieving consistent **weld quality** and **arc stability** when welding with CO2.

Are there any drawbacks to using ER70S-6 with 100% CO2?

While highly effective, using ER70S-6 with 100% CO2 can have some minor drawbacks compared to argon-rich mixtures. It may produce more spatter, requiring additional post-weld cleanup. The arc can also be somewhat harsher and less stable, particularly at lower amperages, potentially leading to a less smooth bead appearance. However, for many industrial applications, the benefits of cost-effectiveness and deep penetration often outweigh these considerations.