Tungsten Electrodes
Tungsten is a rare metallic element used for manufacturing TIG welding electrodes. The TIG process relies on tungsten’s hard-
ness and high-temperature resistance to carry the welding current to the arc. Tungsten has the highest melting point of any
metal, 3,410 degrees Celsius.
Tungsten electrodes are nonconsumable and come in a variety of sizes, they are made from pure tungsten or an alloy of
tungsten and other rare earth elements. Choosing the correct tungsten depends on the material being welded, the amount
of amps required and whether you are using AC or DC welding current.
Tungsten electrodes are colour-coded at the end for easy identication.
Below are the most commonly used tungsten electrodes found in the New Zealand and Australian market.
Thoriated tungsten electrodes (AWS classication EWTh-2) contain a minimum of 97.30 percent tungsten and 1.70 to 2.20
percent thorium and are called 2 percent thoriated. They are the most commonly used electrodes today and are preferred for
their longevity and ease of use. Thorium increases the electron emission qualities of the electrode, which improves arc starts
and allows for a higher current-carrying capacity. This electrode operates far below its melting temperature, which results in
a considerably lower rate of consumption and eliminates arc wandering for greater stability. Compared with other electrodes,
thoriated electrodes deposit less tungsten into the weld puddle, so they cause less weld contamination.
Thorium however is a low-level radioactive hazard and many users have switched to other alternatives. Regarding the
radioactivity, thorium is an alpha emitter but when it is enclosed in a tungsten matrix the risks are negligible. Thus holding
a stick of Thoriated tungsten in your hand should not pose a great threat unless a welder has open cuts on their skin. Thori-
ated tungsten should not get in contact with open cuts or wounds. The more signicant danger to welders can occur when
thorium oxide gets into the lungs. This can happen from the exposure to vapours during welding or from ingestion of mate-
rial/dust in the grinding of the tungsten. Follow the manufacturer’s warnings, instructions, and the Material Safety Data Sheet
(MSDS) for its use.
Ceriated (Color Code: Orange)
Ceriated tungsten electrodes (AWS classication EWCe-2) contain a minimum of 97.30 percent tungsten and 1.80 to 2.20
percent cerium and are referred to as 2 percent ceriated. Ceriated tungstens perform best in DC welding at low current set-
tings. They have excellent arc starts at low amperages and become popular in such applications as orbital tube welding, thin
sheet metal work. They are best used to weld carbon steel, stainless steel, nickel alloys, and titanium, and in some cases it can
replace 2 percent thoriated electrodes. Ceriated tungsten is best suited for lower amperages it should last longer than Thori-
ated tungsten higher amperage applications are best left to Thoriated or Lanthanated tungsten.
Lanthanated (Color Code: Gold)
Lanthanated tungsten electrodes (AWS classication EWLa-1.5) contain a minimum of 97.80 percent tungsten and 1.30 per-
cent to 1.70 percent lanthanum, and are known as 1.5 percent lanthanated. These electrodes have excellent arc starting, a low
burn o rate, good arc stability, and excellent re-ignition characteristics. Lanthanated tungstens also share the conductivity
characteristics of 2 percent thoriated tungsten. Lanthanated tungsten electrodes are ideal if you want to optimise your weld-
ing capabilities. They work well on AC or DC electrode negative with a pointed end, or they can be balled for use with AC sine
wave power sources. Lanthanated tungsten maintains a sharpened point well, which is an advantage for welding steel and
stainless steel on DC or AC from square wave power sources.
Zirconiated (Color Code: White)
Zirconiated tungsten electrodes (AWS classication EWZr-1) contain a minimum of 99.10 percent tungsten and 0.15 to 0.40
percent zirconium. Most commonly used for AC welding Zirconiated tungsten produces a very stable arc and is resistant
to tungsten spitting. It is ideal for AC welding because it retains a balled tip and has a high resistance to contamination. Its
current-carrying capacity is equal to or greater than that of thoriated tungsten. Zirconiated tungsten is not recommended for
DC welding.
Tungsten Electrodes Rating for Welding Currents
Tungsten DC Current Amps AC Current Amps AC Current Amps
Diameter Torch Negative Un-Balanced Wave Balanced Wave
mm 2% Thoriated 0.8% Zirconiated 0.8% Zirconiated
3/64” (0.040”) 15 - 80 15 - 80 20 - 60
1/16” (.062” & .060”) 70 -150 70 - 150 60 - 120
3/32” (.93”) 150- 250 140 - 235 100 - 180
1/8” (.125”) 250 - 400 225 - 325 160 - 250
5/32” (.156”) 400 - 500 300 - 400 200 - 320
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