What is the primary purpose of the filler rod in GTAW?

The primary purpose of the filler rod in Gas Tungsten Arc Welding (GTAW) is to provide additional material for the weld joint. When welding, especially in the case of thicker materials or when creating a strong joint, it's often necessary to add filler material to ensure the joint is robust and can withstand the intended loads and stresses. The filler rod melts and flows into the joint, bonding with the base metals and reinforcing the weld. This additional material also helps in achieving the desired weld bead shape, penetration, and overall quality of the weld.

Understanding the role of the filler rod is crucial for anyone performing GTAW, as it significantly impacts the mechanical properties and integrity of the weld.