WP Tungsten Electrodes WT20, WP, WC10, WC15, WC20, WL20, WY20 Diameter 0.8 ~ 12.0 mm ISO 9001:2000SGS WP tungsten electrode is the most commonly used welding electrode.1) 2% thoriated tungsten contains a nominal 2wt-% or thorium oxide (tho2) that is evenly dispersed throughout the entire length of the tungsten. The most common type of tungsten used today. Provides excellent resistance from weld ...