What is the consequence of using unclean base metal in GTAW?

Using unclean base metal in Gas Tungsten Arc Welding (GTAW) can indeed lead to decreased weld strength. When the base metal contains contaminants such as rust, grease, oil, paint, or oxidation, these impurities can interfere with proper fusion between the materials during the welding process. As the arc forms and the metal is heated, these contaminants can turn into gas or slag, which can create voids or inclusions within the weld.

These voids and inclusions are internal weaknesses that compromise the integrity of the weld, potentially leading to failures under stress or pressure. In contrast, a clean base metal allows for better penetration and a stronger bond between the two pieces being welded. Therefore, maintaining cleanliness of the base metal is critical in achieving high-quality welds that ensure structural reliability and performance.