Why is cleaning prior to welding particularly crucial in GTAW?

Cleaning prior to welding is particularly crucial in Gas Tungsten Arc Welding (GTAW) because it removes contaminants to ensure strong welds. The presence of contaminants such as oil, grease, rust, and oxidation on the base metals can severely compromise weld integrity. These foreign substances may cause defects like porosity, lack of fusion, and weak areas that can lead to weld failures.

For GTAW, which uses a non-consumable tungsten electrode and often requires a clean and precise application of the filler metal, a clean surface is vital for establishing a strong bond between the pieces being welded. When the surfaces are contaminated, the welding arc may not generate the necessary heat effectively, resulting in inadequate penetration or fusion. Therefore, performing a thorough cleaning before welding not only contributes to the overall quality of the weld but also enhances the safety and reliability of the welded structures.