How To Choose The Right Tungsten Wire For TIG Welding
One of the most important things a welder can do when first learning the GTAW technique is to understand the properties of the tungsten being used and make a selection based on the needs at hand. Many people are overwhelmed or confused by the various types of tungsten available. Hopefully, I can provide some help in guiding you on the various options, their capabilities, and my personal experience.
What is Tungsten?
To choose tungsten correctly we must first understand what tungsten is. Tungsten is explained by Wikipedia as:
“Tungsten, or wolfram,is a chemical element with the symbol W and atomic number 74. The name tungsten comes from the former Swedish name for the tungstate mineral scheelite, tungsten which means “heavy stone”. Tungsten is a rare metal found naturally on Earth almost exclusively combined with other elements in chemical compounds rather than alone. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include wolframite and scheelite.
The free element is remarkable for its robustness, especially because it has the highest melting point of all the elements discovered, melting at 3,422 °C (6,192 °F; 3,695 K). It also has the highest boiling point, at 5,930 °C (10,710 °F; 6,200 K). Its density is 19.25 times that of water, comparable with uranium and gold, and much higher (about 1.7 times) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material (under standard conditions, when uncombined), making it difficult to work. ”
What does it all mean?
Tungsten is hard and brittle. Larger pieces of tungsten can break if dropped on a concrete floor. If tungsten becomes contaminated during the welding process, removing the contaminated portion is very easy. One end of the tungsten can be placed on the edge of a hard surface and then broken off with a tool or piece of metal.
Tungsten can withstand heat. Tungsten is one of the few materials on earth that would be able to withstand the extreme temperatures of welding.
Tungsten is very dense. This is important because the density of the tungsten affects the rate at which current passes through it. Also the efficiency of the material at passing current with very little resistance. This helps to ensure a stable arc.
Now, on to the choice of the tungsten type.
The old-school technique for Aluminum is using pure tungsten. Pure tungsten needs to be balled on the end prior to welding aluminum. Pure tungsten is also only good for AC current as you can see on the tungsten selection chart. 2% Thoriated tungsten is also very popular for DC welding, particularly for mild and stainless steel. The properties of thoriated tungsten allow for an extremely stable arc, the downside being they are made with radioactive material. By grinding a thoriated tungsten you are releasing radioactive material into the atmosphere and possibly breathing it in. By using something like a 2% lanthanated tungsten you are getting the best of both worlds. A nice stable arc that maintains a short point, even on AC welding.
Many other types of tungsten are used for specialty items. Tungsten is relatively inexpensive and many companies will offer you a free sample if you just ask. On a machine like The TIG-200 AC DC TIG welder, you can try a few different kinds out on your day-to-day material and see if making a change makes life any easier.
The TIG-200 AC DC TIG welder typically comes with a 2% Lanthanated tungsten. This will allow you to weld Mild steel, stainless, or aluminum right out of the box simply by adding argon shielding gas.
If you have any questions please don’t hesitate to reach out to our friendly customer support team. They are knowledgeable and can also answer lots of consumable questions you may have!
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