What effect does CO2 have on penetration when used with FCAW?

When using carbon dioxide (CO2) as a shielding gas in flux-cored arc welding (FCAW), it leads to deeper penetration. This is primarily due to the chemical and thermal characteristics of CO2. The gas has a higher ionization potential, which means that it can provide a more stable arc. This stability enhances heat input to the workpiece, resulting in better fusion and deeper penetration of the weld bead.

Moreover, CO2's properties allow it to promote a more focused heat source, which increases the energy concentration on the weld pool. As a result, the molten metal can penetrate deeper into the base material, helping to achieve strong welds with greater depth. This characteristic of CO2 is advantageous for welding thicker materials or where a stronger joint is essential.

In contrast, other shielding gases or mixtures might not provide this level of penetration, which can be beneficial for specific welding applications depending on material thickness and joint design.