How to Select Tungsten Electrode in TIG Welding (III): Lanthanated Tungsten (Gold 1.5% or Blue 2.0%)

Lanthanted Tungsten (Color Code: Gold 1.5% or Blue 2.0%)

Lanthanated tungsten electrodes (AWS classification EWLa-1.5 or EWLa-2.0) contain a minimum of 97.80 percent tungsten and 1.30 percent to 2.0 percent lanthanum, or lanthana, and are known as 1.5 percent or 2.0 percent lanthanated. These electrodes have excellent arc starting, a low burnoff rate, good arc stability, and excellent re-ignition characteristics—many of the same advantages as ceriated electrodes. Lanthanated electrodes also share the conductivity characteristics of 2 percent thoriated tungsten. In some cases, 1.5 percent lanthanated can replace 2 percent thoriated without having to make significant welding program changes.

Lanthanated tungsten electrodes are ideal if you want to optimize your welding capabilities. They work well on AC or DC electrode negative with a pointed end, or they can be balled for use with AC sine wave power sources. Lanthanated tungsten maintains a sharpened point well, which is an advantage for welding steel and stainless steel on DC or AC from square wave power sources.

Unlike thoriated tungsten, these electrodes are suitable for AC welding and, like ceriated electrodes, allow the arc to be started and maintained at lower voltages. Compared with pure tungsten, the addition of 1.5 percent lanthana increases the maximum current-carrying capacity by approximately 50 percent for a given electrode size.

How to Select Tungsten Electrode in TIG Welding (II): Pure Tungsten (Green)

Pure Tungsten (Color Code: Green)

Pure Electrode Tungsten electrode (AWS classification EWP, alloying color code: Green) consists of about 99.5% tungsten. It has the highest consumption rate of all electrodes, but typically less expensive than their alloyed counterparts.

These electrodes form a clean, balled tip when heated and provide great arc stability for AC welding with a balanced wave. Pure tungsten also provides good arc stability for AC sine wave welding, especially on aluminum and magnesium. It is not typically used for DC welding because it does not provide the strong arc starts associated with thoriated or ceriated electrodes.

How to Select Tungsten Electrode in TIG Welding (I)

It is crucial to Choose a tungsten electrode in successful gas tungsten arc welding (GTAW) or Tungsten Inert Gas welding (TIG).  The electrode choices are pure tungsten (Green), 2% thoriated (Red), 2% ceriated (Gray or Orange), 1.5 percent lanthanated (Gold) or 2% lanthanated (Blue) and rare earth. In addition, tip preparation is critical.

These nonconsumable electrodes are available in a range of sizes and lengths and are composed of either pure tungsten or an alloy of tungsten by other rare-earth elements and oxides. Choosing an electrode for GTAW depends on the base material type and thickness and whether you weld with alternating current (AC) or direct current (DC). Which one of three end preparations you choose, balled, pointed, or truncated, also is crucial in optimizing the results and preventing contamination and rework.