Zirconiated tungsten electrodes (AWS classification EWZr-1) are primarily used for AC TIG welding of aluminum and magnesium alloys. They are easily identified by a white or sometimes brown tip.
Key Features and Characteristics
Primary Use: AC Welding Zirconiated tungsten is specifically designed for alternating current (AC) applications, where it performs well, especially under high-load current conditions. It is not recommended for DC welding.
Excellent Arc Stability: It produces an extremely stable arc that resists wandering or "spitting" (transferring small particles of tungsten into the weld puddle), which helps minimize weld contamination.
Balled Tip Formation: The electrode tip naturally forms a clean, balled shape during AC welding, which is ideal for stabilizing the arc when using older transformer-based power sources.
High Resistance to Contamination: Zirconium oxide helps the electrode resist contamination from the base metal, even when welding in confined spaces where metal vapors might otherwise condense on the electrode.
Current Capacity: It handles higher amperage loads than pure tungsten electrodes and offers a current-carrying capacity equal to or greater than that of thoriated tungsten.
Non-Radioactive: Unlike thoriated tungsten, zirconiated tungsten is non-radioactive, making it a safer alternative.
Composition
Zirconiated electrodes contain a minimum of 99.10% tungsten and 0.15% to 0.40% zirconium oxide (ZrO). The WZ8 grade contains approximately 0.8% zirconium oxide.
Primary Applications
Zirconiated tungsten is the ideal choice for TIG welding:
Aluminum and its alloys.
Magnesium and its alloys.
Applications where tungsten contamination of the weld must be minimized.