The tungsten electrode is what makes TIG welding so adaptable to different purposes, and selecting the right electrode can enhance the effectiveness of the process.

Like any other welding process, TIG welding relies on the right equipment to get the job done properly, and from the power source to the TIG torch and cables, each component plays a critical role. But at the core of the TIG welding process is something unique: the tungsten electrode. This non-consumable metallic element has the highest melting point of any metal (3,410 degrees Celsius), making its hardness and high-temperature resistance the ideal option for carrying the welding current to the arc.

Choosing a specific type of tungsten for your TIG welding application doesn’t have to be difficult, but it depends on you having a little know-how. To begin, tungsten electrodes come in a variety of diameters — typically ranging from 0.040- to 5/32-inch — and they are available in industry-standard lengths of seven inches. Custom lengths are available, too, but they tend to cost more. The electrodes are composed either of pure tungsten or a hybrid of tungsten and other rare earth elements and oxides (all discussed below.) To eliminate confusion between the various types, each electrode is color-coded, with the color appearing at the tip of each electrode.

Following here is a description of the various types of tungsten electrodes, including their characteristics, typical applications and most appropriate weld settings, along with recommendations for proper preparation.

Pure tungsten (color code: green)
Pure tungsten electrodes have an AWS (American Welding Society) classification of EWP and typically are less expensive than their “alloyed” counterparts. They contain 99.50% tungsten and have the highest consumption rate of all electrodes, and provide a clean, balled tip when heated. This shape offers especially good arc stability for AC welding with a balanced waveform. Pure tungsten electrodes also provide good arc stability for AC sine wave welding on aluminum and magnesium. They are not, however, used for DC welding.

2% Ceriated (color code: orange)
Containing a minimum of 97.30% tungsten and 1.80 to 2.20% cerium, 2% ceriated tungsten electrodes perform best in DC welding, but they can be used proficiently in AC, too. These electrodes have an AWS classification of EWCe-2 and offer excellent arc starts at low amperages, making them popular in orbital tube and pipe manufacturing, thin sheet metal work or jobs that require the welding of small and delicate parts. 2% ceriated tungsten works well for welding carbon and stainless steels, nickel alloys and titanium.

In recent years, pointed 2% ceriated tungsten has replaced balled pure tungsten for AC welding on aluminum, as it provides approximately 30-40% more current-carrying capacity than the pure tungsten at the same diameter.

1.5% Lanthanated (color code: gold)
1.5% lanthanated tungsten electrodes have excellent arc starting, low-burn-off rate, good arc stability, and excellent re-ignition characteristics — many of the same advantages as ceriated electrodes. 1.5% lanthanated electrodes also closely resemble the conductivity characteristics of 2% thoriated tungsten (discussed later), meaning, in some cases, it can replace 2% thoriated without having to make significant welding program changes. These electrodes have an AWS classification of EWLa-1.5 and contain a minimum of 97.80% tungsten and 1.30 to 1.70% lanthanum, or lanthana.

1.5% lanthanated electrodes 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. They also maintain a sharpened point well, which is an advantage when welding steel and stainless steel on DC or the AC from squarewave power sources.

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

Rare earth (color code: gray)
Rare earth tungsten electrodes contain unspecified additives of rare earth oxides or hybrid combinations of different oxides that manufacturers must identify on all packaging by both additive and percentage. Depending on the type of additives, rare earth tungsten can provide benefits that include: a stable arc in both AC and DC processes; greater longevity than thoriated tungsten; the ability to use a smaller-sized diameter tungsten for the same job; use of a higher current for similar-sized tungsten; and less tungsten spitting. Rare earth tungsten has an AWS classification of EWG.