Understanding tungsten electrode classifications

Updated: Oct 25, 2021

Welding filler rod and electrode classification understanding is pretty common among welders, but a topic which is very seldom mentioned is tungsten classification. There are a variety of tungsten electrode chemical composition variations that are needed in order to satisfy the requirements of each material that is to be welded. The most common tungsten chemical combination is 2% thoriated which is used to weld most mild carbon steels and alloys, most commonly identified by the red ½ long marking on one end of the tungsten electrode.

Different types of tungsten
Different types of tungsten (Figure 1)

Do you know how to read a tungsten electrode’s material composition and electrode classification number for the GTAW process? Figure 1 above shows a prime example of a 2% thoriated tungsten electrode (red marking).

Tip: The letter W is used for Tungsten in the table of elements as pictured in Figure 2 below.

Tungsten symbol in table of elements (Figure 2)
Tungsten symbol in table of elements (Figure 2)

Finally, the anatomy of the electrode classification for Tungsten in figure 3 below. What kind of chemical composition does the tungsten described below have?

Tungsten electrode classification
Tungsten electrode classification (Figure 3)

If you answered 2% Ceriated you are correct, we can see that CeO2 is the chemical name for Ceriated Oxide therefore that makes up the chemical content of the electrode. I hope this comes in handy for you as you broaden your understanding of the GTAW process.


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