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What Is … TIG Welding?

TIG arc between tungsten electrode and workpiece

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:

Tungsten/lanthanum oxide electrodes are colored blue

  • 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.”

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57 Comments

  • Reply
    Jerald Fernandes
    22. May 2018 at 17:32

    Very nice to read these basics. Helps a lot

    • Reply
      redakteur
      23. May 2018 at 6:46

      Thank you! Great to hear that!

  • Reply
    EARL LOWERY
    18. June 2018 at 17:45

    Very helpful videos thank you

    • Reply
      redakteur
      19. March 2019 at 7:16

      Thank you!

  • Reply
    Nathan Martin
    16. March 2019 at 11:33

    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.

    • Reply
      redakteur
      19. March 2019 at 7:17

      Thank you for your nice feedback! Glad you like these kind of blog posts!

  • Reply
    James Johnson
    14. September 2019 at 2:43

    Very helpful information. But we must focus on our safely first. Anyway thanks for sharing. Keep it up.

    • Reply
      redakteur
      13. July 2020 at 8:38

      Thank you for your feedback!

  • Reply
    aman josh ji
    16. May 2020 at 14:10

    love your post

    • Reply
      redakteur
      13. April 2021 at 9:18

      Thank you!

    • Reply
      Creamy
      25. June 2021 at 11:51

      Wonderful information ❤️

  • Reply
    Oliver TIG
    11. July 2020 at 16:14

    It is awesome to get to know about all the basics of Tig welding. Being a novice in this field i am highly thankful.

    • Reply
      redakteur
      13. July 2020 at 8:38

      Thank you very much!

  • Reply
    Abandi
    29. August 2020 at 19:46

    I love Tig Welding and I hope to make a career from it I am just 19 now and had an accident for not wearing a helmet. Anyhow this insight is meaningful Thanks.

    • Reply
      redakteur
      13. April 2021 at 9:19

      Thank you very much for your honest words!

  • Reply
    jason
    11. September 2020 at 14:46

    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!

    • Reply
      redakteur
      14. September 2020 at 7:40

      Thank you very much for your feedback!

  • Reply
    Jimmy
    30. September 2020 at 10:38

    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.

    • Reply
      redakteur
      15. October 2020 at 9:20

      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 🙂

  • Reply
    jack
    20. November 2020 at 11:07

    great You have explained tig welding in a very clear way.

    • Reply
      redakteur
      24. November 2020 at 8:28

      Thanks, Jack! We are happy to hear that you like it 🙂

  • Reply
    Alisa
    18. January 2021 at 15:36

    the great explanation you have cleared my confusion.

    • Reply
      redakteur
      19. January 2021 at 9:47

      Thank you very much, Alisa. Glad to hear that!

  • Reply
    ketan
    19. January 2021 at 6:08

    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.

    • Reply
      redakteur
      19. January 2021 at 9:48

      Thank you very much for your feedback! There will be definitely more in the future… 😉

  • Reply
    Hatim
    1. March 2021 at 15:16

    Quite Informational Very Good. Keep up the good work.

    • Reply
      redakteur
      29. March 2021 at 7:27

      Thank you very much!

  • Reply
    David
    1. March 2021 at 15:18

    Very Good Article good work.

    • Reply
      redakteur
      29. March 2021 at 7:27

      Thank you very much!

  • Reply
    sakib
    23. March 2021 at 14:49

    Well, it’s good! Thanks for sharing such useful information, its really helpful. Keep posting…..

    • Reply
      redakteur
      29. March 2021 at 7:27

      Thank you very much for your feedback!

  • Reply
    sakib
    25. March 2021 at 7:05

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    • Reply
      redakteur
      29. March 2021 at 7:28

      Thank you very much! Glad to hear that!

  • Reply
    Dave Walker
    10. April 2021 at 21:33

    Very nice article cleared some of my confusions. A great resource for tig welders indeed.

    • Reply
      redakteur
      13. April 2021 at 9:19

      Thank you very much!

  • Reply
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      redakteur
      13. April 2021 at 15:32

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  • Reply
    Alade Pete
    25. June 2021 at 11:41

    I’m so glad I stumbled upon this piece of beautiful write-up, how overwhelmed I am right now because this is part of my research work. I have read more about Tungsten Inert Gas Welding from different web pages but yours is more detailed and simple to understand, thanks so much for your wonderful information.

    • Reply
      redakteur
      28. June 2021 at 14:39

      Thank you very much for your kind feedback! Really appreciate it. Have a nice day!

  • Reply
    Binary
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    • Reply
      redakteur
      28. June 2021 at 14:39

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    Alex Hales
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