What Is … TIG Welding?

What does “TIG” stand for? Why is inert gas used in this process? And what role do tungsten electrodes play? Welding is complex but the basics are actually pretty easy to understand. The Fronius “What is …?” series helps to build an understanding of welding and to maintain an overview of the basic terms.
Tungsten Inert Gas Welding
TIG welding is a process that enables top-quality weld seams. The arc burns between a temperature-resistant, non-melting tungsten electrode, and the workpiece. The inert shielding gas that gives the process its name creates an oxygen-free gas atmosphere and prevents chemical reactions with the liquid weld pool. This results in smooth, level, and non-porous weld seams. The filler metal is guided manually or using a wirefeeder.
TIG welding can be used for all metals that are suitable for welding. The biggest area of application here is stainless steels, and the processing of non-ferrous metals such as aluminum, copper, and brass. TIG is primarily used for root passes as the seams are smooth and non-porous, and can therefore withstand dynamic forces well.
Inert Shielding Gas
For TIG welding, reaction-free (inert) shielding gas is used. The gas atmosphere has a protective function, preventing chemical reactions with the liquid weld pool and the heated material. This guarantees high-quality weld seams.
The noble gases argon and helium, or a mixture of these gases, are used as shielding gases. Argon is used most frequently as it provides optimal conditions for ignition and ensures a particularly stable arc. Helium conducts heat more efficiently than argon and therefore ensures deep and wide penetration.
Tungsten Electrodes
The tungsten electrode is at the core of TIG welding. At 3380 degrees Celsius, tungsten has the highest melting point of any pure metal in the periodic table. This means the electrode can emit an arc that heats and liquefies the workpiece without itself melting away.
The electrodes are produced using a sintering process. They can also be alloyed using oxidic additives to improve their properties. The electrodes are color-coded according to the alloy used:

- Pure tungsten (WP) (green):
Flat, spherical electrode surface
Ignition problems with DC
Low current-carrying capacity - Thorium oxide (WT 20) (red):
Excellent ignition properties
Significantly higher current-carrying capacity than pure tungsten electrodes
Slightly radioactive (alpha emitters) - Cerium oxide (WC 20) (gray):
Similar properties to thorium
Non-radioactive - Lanthanum oxide (WL 20) (blue):
Longer service life than tungsten/thorium or tungsten/cerium oxide electrodes
Poorer ignition properties
High Frequency Ignition
One particular characteristic of TIG is that the arc can be ignited without contact. A series of fast high-voltage pulses cause a spark to jump across to the workpiece and the arc then stabilizes itself. High frequency ignition is extremely easy for the welder to handle. The electrode cannot stick to the workpiece, is not contaminated, and no tungsten inclusions are created in the seam.
You can read more about the advantages of the TIG process in the Fronius blog article “TIG Welding: Top-Quality Connections.”
20 Comments
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Very nice to read these basics. Helps a lot
Thank you! Great to hear that!
Very helpful videos thank you
Thank you!
I’m glad you shared this helpful information with us. Please keep us up to date like this. This is actually a good and useful piece of information. thank you for sharing.
Thank you for your nice feedback! Glad you like these kind of blog posts!
Very helpful information. But we must focus on our safely first. Anyway thanks for sharing. Keep it up.
Thank you for your feedback!
It is awesome to get to know about all the basics of Tig welding. Being a novice in this field i am highly thankful.
Thank you very much!
You have explained tig welding in a very clear way.
I am a newbie and I hope i will improve my skills with it. Good work!
Thank you very much for your feedback!
Great explanation by you. it really helps beginners like me. Impressed by your work and hope you will definitely work like this in the future.
God bless you.
Dear Jimmy, we are happy to hear that you like this blog article. We are trying to do our best to keep it up – for example with our basics article about MIG/MAG welding or about how to correctly apply the welding settings. I hope those are helpful too 🙂
great You have explained tig welding in a very clear way.
Thanks, Jack! We are happy to hear that you like it 🙂
the great explanation you have cleared my confusion.
Thank you very much, Alisa. Glad to hear that!
This is the perfect article for beginners, Thanks for the same.
Will be looking for further blog posts on how to choose tungsten?, Setting up like Gas flow, Current, Angle etc.
Thank you very much for your feedback! There will be definitely more in the future… 😉