What type of material may experience issues due to oxides preventing the molten weld pool from flowing together?

Aluminum is particularly susceptible to issues from oxides during the Gas Tungsten Arc Welding (GTAW) process. It naturally forms a thin layer of aluminum oxide on its surface that can significantly interfere with welding. This oxide layer does not melt at the same temperatures as aluminum, resulting in a barrier that prevents proper flow of the molten weld pool. This can lead to poor fusion, inclusions, or defects in the weld joint.

Aluminum oxide has a melting point that is much higher than that of the aluminum base metal, which means that when welding, the welder has to overcome this barrier to achieve a good weld. If not adequately removed, this oxide layer can impede the weld from flowing together properly, leading to weak joints and structural issues.

In contrast, materials like steel and iron do not typically experience the same degree of oxide-related issues during GTAW, as their oxide layers (like rust on steel) can often be removed more easily and don’t create the same challenges in the welding process as aluminum oxide does. While copper can also develop oxides, aluminum is the most problematic in this context, primarily because of the strength of its oxide layer and the characteristics of aluminum itself during the welding process.