NP541 - Pure Tungsten EWP Green Electrodes 1/8" for Aluminum TIG Welding

Technical Overview of Pure Tungsten (EWP) Electrodes

The Pure Tungsten Electrode, identified by its Green color code and the AWS classification EWP, represents the original form of tungsten electrode used in Gas Tungsten Arc Welding (GTAW). Composed of at least 99.5% pure tungsten, this electrode contains no alloying oxides (such as thorium, lanthanum, or cerium). This high purity results in a unique set of thermal and electrical properties that make it the standard choice for specific welding applications, particularly those involving Alternating Current (AC).

One of the defining characteristics of pure tungsten is its electron emission mechanism. Unlike rare-earth doped electrodes which lower the work function to emit electrons easily, pure tungsten requires higher temperatures to maintain thermionic emission. Consequently, the tip of the electrode naturally melts to form a hemispherical "ball" when used with AC current. This balled geometry is highly desirable for AC welding on aluminum and magnesium because it spreads the arc over a wider surface area, reducing the current density and providing a stable, wandering-free arc on sine-wave power sources.

These 1/8" (3.2mm) electrodes are manufactured to strict tolerances to ensure consistent chemical composition and straightness. While pure tungsten has largely been replaced by rare-earth alternatives for DC welding due to its tendency to degrade under high heat without the stabilizing oxides, it remains a superior choice for traditional transformer-based rectifiers welding non-ferrous metals. It provides good arc stability when used with a balanced wave or continuous high-frequency stabilization.

Application Notes

It is important to note that Pure Tungsten is not recommended for DC welding (Direct Current), as it does not provide reliable arc starts or maintain a sharp point under DC polarity. However, for AC welding of aluminum alloys and magnesium, specifically with older technology power sources, it offers excellent performance and contamination resistance.