When first learning the art of GTAW, one of the most important things a welder can do, is to understand the properties of the tungsten they are using and make a selection based on the need at hand. Many people feel overwhelmed or confused by the various types of tungsten available. Hopefully I can help shed some light on the various options, their functions, and my personal experience to help guide you.
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 the fact that 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 that of 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 all of this mean!?
Tungsten is hard and very brittle. If dropped on a concrete floor, larger pieces of tungsten have been known to break. If contamination occurs to the tungsten during welding, removal of the contaminated piece is extremely easy. The end can be placed on the edge of a hard surface and 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 choosing 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 a 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 GTAW Stick 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 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!