PURE Tungsten Color Coded GREEN, are best suited for AC Tig welding applications. Pure Tungsten, Green, AWS Class EWP, AC welding applications. Least expensive of all electrodes. Applications: aluminum and magnesium alloys.THORIATED Tungsten Color Code RED, YELLOW, or ORANGE, are best suited for DC Tig welding applications.2% Thoriated, Red, AWS Class EWTH-2, DC welding applications. The most common type of electrode used today. Applications: carbon & stainless steel, nickel alloys and titanium.