Use and Identify Tungsten Electrodes Correctly in Arc Welding

Gas tungsten arc welding (GTAW) and plasma arc welding (PAW) usually use nonconsumable tungsten electrode in welding process. These tungsten electrodes have a variety of compositions and shape, and each composition serves a specific purpose:

Pure tungsten electrodes (AWS classification EWP) contain 99.50 percent tungsten. They provide good arc stability for AC welding on aluminum and magnesium. Their color designation is green.

2% thoriated tungsten electrodes (AWS classification EWTh-2) contain 1.70 to 2.20 percent thorium and are the type most commonly used. Compared with pure tungsten, they work exceptionally well for DC electrode negative or straight polarity on carbon and stainless steels. Their color designation is red.

2% ceriated tungsten electrodes (AWS classification EWCe-2) contain 1.80 to 2.20 percent cerium. They has best performance in DC welding at low current settings, but can be used in AC processes as well. Their color designation is orange.

1.5% lanthanated tungsten electrodes (AWS classification EWLa-1.5) contain 1.30 to 1.70 percent lanthanum or lanthana. These have many of the same advantages as ceriated electrodes and closely resemble the conductivity characteristics of 2 percent thoriated tungsten. Their color designation is gold.

Zirconiated tungsten electrodes (AWS classification EWZr-1) contain 0.15 to 0.40 percent zirconium. It is suitable for AC welding, but no recommended zirconiated for DC welding. Their color designation is brown.