Selecting the proper tungsten electrodes will greatly improve weld quality and productivity while lowering costs for your Gas Tungsten Arc Welding (GTAW/TIG).

The first thing to consider when selecting a tungsten electrode for your TIG/GTAW welding application is to buy from a trusted supplier. Although tungsten electrodes may look the same from one company to another, high-quality tungsten has been manufactured to ensure a very small grain structure which allows for better migration of oxides to the tip, and overall improved arc performance.

With high-quality tungsten, you’ll also experience easier arc starting, improved arc time and better weld quality with minimized contamination. Make sure that your supplier offers tungsten electrodes from the world’s finest producers and meet or exceed ISO 6848 and AWS A5.12 standards. And be sure to ask about traceability.

Since the development of the TIG welding process, many improvements have been made in the production of electrodes. Most significantly is the addition of oxides to pure tungsten, creating tungsten alloys that provide the same level of emission as pure tungsten at much lower temperatures, improving the arc time of the electrode, and improving arc stability.

Each oxide has a different physical characteristic effecting tungsten performance. Electrodes are color coded, indicating the type of oxide used in the mix. Note that color-coding is not standardized for all mixes and varies from the U.S. to Europe and Japan.

For most hand-held welding operations, choose a tungsten electrode that performs well for all metals and with all welding power sources, such as the ArcTime™ Hybrid Tungsten Electrode.

For other applications, particularly automated welding, the best way to determine which tungsten alloy is best suited for your application is through testing. The following list is provided as a guide.

ArcTime™ Hybrid (Color Code: Sky Blue (US) Not standardized) is a non-radioactive state-of-the-art formula combining rare earth materials with tungsten to produce the best all-purpose tungsten electrode on the market. Experience reliable arc starting even after numerous ignitions. This tungsten blend works with all metals, and on all machines.

4% Thoriated (Color Code: Not standardized in US or Japan. Orange-Europe) is a radioactive tungsten formula is not commonly used.

2% Thoriated (Color Code: Red-US, Europe and Japan) is a formula popular for general purpose electrodes due to the excellent arc behavior and good tip life. This is a radioactive formula, however. Vapors, grinding dust and disposal of thorium dioxide raise health, safety and environmental concerns. Use only when contractually required by FAR specification.

2% Lanthanated (Color Code: Blue-US, Not standardized in Europe, Yellow/Green-Japan) is a good general purpose non-radioactive replacement for 2% Thoriated. It has excellent ignition performance, low-burn-off rate, excellent re-ignition, and good service life.

1.5% Lanthanated (Color Code: Gold-US, Not standardized in Europe or Japan) Another good general-purpose non-radioactive replacement for 2% Thoriated, and similar in performance to 2% lathanated. It features excellent ignition and re-ignition properties and good service life.

1% Lanthanated (Color Code: Black-US, Europe and Japan) is a non-radioactive tungsten formula is not commonly used.

2% Ceriated (Color Code: Orange-US, Gray-Europe and Japan) is a tungsten formula good for low-amp, DC orbital tube, pipe, thin sheet, and small part applications. This formula offers low current capacity, low arc ignition, good arc stability.

I% Zirconiated (Color Code: Brown-US, White-Europe) Not standardized in Japan) is used for radiographic-quality welding where tungsten contamination must be minimized. Balls-up easily in AC applications, good arc starting and current capacity.

Pure Tungsten (Color Code: Green-US, Europe and Japan) has a high work-function which makes it difficult to start and maintain a stable arc. High burn-off rate results in short service life of the tungsten electrode.

Once you’ve determined the blend of tungsten that best suits your welding application, you’ll next need to decide which diameter tungsten electrode is best.

Tungsten is generally sold in packages of 10 pieces in a variety of standard diameters from .020” to .250” and in lengths of 3, 6, 7, 12, 18 and 24 inches. The most common length is 7.00″(175mm). The most common diameters are: .040″ (1.0mm), 1/16″ (1.6mm), 3/32″ (2.4mm), I/8″ (3.2mm), 5/32″ (4.0mm), and 3/16″ (4.8mm)

Electrode diameter affects welding performance and weld bead shape. Again, the best way to determine which tungsten is best suited for your application is through testing, however, the following chart should serve as a general guide.

Different electrode materials will vary slightly from these guidelines. Use of other gases will also change the recommended currents. Use this chart as a general guide. Also keep in mind that for a given amount of amperage, larger diameter electrodes will last longer but will be harder to start. Excessive current will cause the electrode to melt and drop off. Insufficient current will lead to an unstable arc.

As electrode tip geometry greatly affects welds, for optimal performance in automated TIG welding applications, choose pre-ground tungsten electrodes. This will minimize variables and ensure consistent tip geometry– every single time.

For further assistance in selecting the correct tungsten electrode for your welding application, please contact an Arc-Zone.com technician via email at technician@arc-zone.com, phone toll free 800-944-2243 or call worldwide: 760-931-1500.