What is the term for the process of adding filler material in GTAW?

In Gas Tungsten Arc Welding (GTAW), the process of adding filler material is specifically termed "filler metal addition." This process involves introducing a filler rod or wire into the weld pool to enhance the weld joint's strength and fill any gaps between the base metals being joined.

Filler metal addition is critical in situations where the joint geometry requires it or when the thickness of the materials exceeds what can be effectively melted by the arc alone. This addition is performed manually or with automated means and must be done carefully to maintain the quality of the weld.

The other terms, while related to welding, describe different aspects or phenomena that occur during the welding process. Weld pool reduction refers to the decrease in the size of the molten metal pool as it solidifies. Arc deflection encompasses the behavior of the welding arc under various influences but does not specifically relate to adding filler material. Weld penetration describes how deep the arc melts into the base metal, which is a different aspect of the welding process than the addition of filler material.