For which material is pure argon used as a shielding gas?

Pure argon is commonly used as a shielding gas when welding aluminum due to its inert properties. Aluminum has a low melting point and is prone to oxidation during the welding process. The use of argon effectively prevents atmospheric contamination and oxidation, resulting in cleaner and stronger welds. Argon does not react with aluminum, which allows for better weld quality and penetration, making it the preferred choice for processes like Gas Tungsten Arc Welding (GTAW) or TIG welding aluminum.

Other materials listed, such as galvanized steel, cast iron, and copper, often require different types of shielding gases that may enhance the welding process and protect against reactions that argon alone would not adequately prevent or address. For instance, galvanized steel may require a gas mixture that can better handle the zinc coating, while other metals might benefit from different inert gases or blends to achieve optimal results during welding.