WP 

Pure Tungsten:
Pure tungsten electrodes (AWS classification EWP) contain 99.50% tungsten, have the highest consumption rate of all electrodes and are typically less expensive than “alloyed” counterparts.
These electrodes form a clean, balled tip when heated and provide great arc stability for AC welding with balanced wave. Pure tungsten also provides good arc stability for AC sine wave welding, especially on aluminum and magnesium, but is not typically used for DC welding (it does not provide as strong of arc starts as thoriated or ceriated electrodes).

Application: Pure Tungsten Electrode are generally used in the welding of aluminum and magnesium alloys (AC) and used under alternating current. but is not typically used for DC welding (it does not provide as strong of arc starts as thoriated or ceriated tungsten electrodes).