What is TIG Welding (GTAW) & How it Works

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The TIG welding process is a highly sophisticated, precise, and versatile arc welding method that joins almost all metals.

In other words, TIG welding is incredible. But, it’s also very challenging.

This article will teach you what TIG welding is, how it works, its applications, and how to get started. Plus, we’ll compare it to MIG welding, discuss TIG welding careers, and share crucial pros and cons of this welding process.

What is TIG Welding?

TIG, or tungsten inert gas, uses a non-consumable tungsten electrode to create an arc and join metal. It requires the use of shielding gas, most commonly pure argon or argon mixed with helium.

This welding process uses direct current (“DC”) and alternating current (“AC”) depending on the metal to be joined.

tig welding process 1

The American Welding Society (“AWS”) classifies TIG welding as “gas tungsten arc welding,” but the abbreviation “GTAW” is commonly used. Initially, the process was named “heliarc,” but that term pops up rarely nowadays. You can read more about heliarc welding here.

The unique aspects of TIG welding are the absence of physical contact between the electrode and the metal pieces and that the electrode is not consumed in the process. As a result, the arc is stable and clean and produces aesthetically pleasing welds. 

Electrodes used in other arc welding processes physically interact with the metal and may involve various fluxing agents, which results in spatter and less control over the welding arc.

How Does TIG Welding Work?

TIG welding works by melting the base metal with an electrical arc formed between the tungsten electrode and the grounded metal (the work clamp closes the circuit).

Let’s break it down…

Tungsten Electrode

Tungsten metal melts at far higher temperatures (3422°C) than metals like steel (1371-1540°C) and aluminum (660°C). So, the tungsten electrode easily tolerates the high heat as it directs the electrical arc into the weld puddle. Plus, as the tungsten gets hotter, the electron emission improves and creates an even more stable, clean arc.

You can shape the welding arc and cone width by grinding the tungsten electrode tip to a point. This metal is easy to shape and retains the desired configuration well. You can modify the heat input and concentration by tailoring the tungsten tip shape, which is a highly beneficial aspect of TIG welding.

tig tungsten electrode tip shape
The image shows how electrode tip shape influences the weld profile

Filler Metal

The TIG welding process can join metals with or without filler metal. The welding arc originating from the tungsten electrode melts the two base metals and fuses them. However, to achieve strong joints, filler metal is usually required.

Adding filler metal is one of the challenging aspects of GTAW. You must add the filler metal by dabbing a filler wire into the weld pool with one hand while controlling the TIG torch with the other.

close up tig welding rod with shielding gas

Touching the tungsten with the filler metal contaminates the electrode, requiring you to stop and regrind the tungsten tip. So, adding the filler metal is tricky because the tungsten tip and the filler wire tip have to be close and move in the same direction without touching.

Shielding Gas

As the name implies, the “tungsten inert gas” welding process requires using an inert shielding gas to protect the tungsten electrode and the molten metal from oxidation. Inert gasses don’t react with the materials used to weld. This protection is essential because it ensures a clean, stable environment for the arc and the molten metal puddle in the joint.

The two most commonly used shielding gasses for TIG welding are argon and helium. Argon is almost perfect and gets the job done in 99% of the cases. However, you may encounter tasks where a helium argon blend can improve penetration. Just know it sacrifices some arc stability.

Where is TIG Welding Used?

Gas tungsten arc welding is typically used for precision welds and joining exotic metals like stainless steel, aluminum, Chromoly, nickel alloys, and magnesium. However, it’s also employed for welding regular mild steel if the joint quality must be absolute. Otherwise, MIG welding is more suitable for mild steel because it’s faster and easier.

The TIG welding process allows total control over the heat input and welding arc. Modern TIG power sources support pulsed TIG, and you can modify the AC balance, frequency, waveforms, and individual amperage output for DCEN and DCEP portions of the AC. Plus, a foot pedal lets you moderate amperage output in real-time as you weld.

Precise heat control is needed for professional thin stock welding, especially with exotic materials. For example, stainless steel retains heat, leading to carbon precipitation that quickly destroys its corrosion resistance. But, if you use pulsed TIG welding, you can control heat input and make perfect stainless steel welds.

Welding Aluminum and Magnesium

Some materials like aluminum or magnesium can only be TIG welded if you wish to achieve maximum joint quality. MIG welding aluminum also works well, but AC TIG welds are king. That’s because the DCEP completely removes surface oxides while DCEN allows them to penetrate the material. MIG welding power sources can’t provide total control like TIG welders.

tig welding ac dcep
The image shows how AC alternates between DCEP and DCEN and how DCEP breaks oxides while DCEN penetrates the metal.

You can perfectly tailor the arc for your specific aluminum or magnesium piece by using AC balance and amplitude control (individually modifying DCEN and DCEP amperage output). This takes experience because you must evaluate the extent of surface oxides and set the proper AC balance and amperage output for each polarity to match the situation. No other arc welding process offers so much control.

Weld Looks

Finally, aesthetics play a significant role when deciding which welding process to use. Stick and flux-cored welding are not an option if you want pretty welds. While MIG welds can look good, TIG welding achieves the best results.

tig welding stainless steel bead with argon

Imagine using the stick welding process to make a bicycle frame. It would be a disaster and require extensive post-weld cleanup. 

But, on the other hand, a skilled TIG welder can make the famous “stack of dimes” bead that requires little to no cleanup. The same goes for car body repairs, interior furniture, or anything else where aesthetics are essential.

Is TIG Different Than MIG Welding?

TIG welding is very different from MIG welding because the MIG welding process uses a consumable electrode that also acts as a filler metal. Unlike TIG, MIG welding relies on an automatic wire feeder that pushes the filler metal wire into the molten weld pool. But, this filler wire is also energized, just like the tungsten electrode in TIG welding.

MIG wire is pushed from the wire feeder, through the lead, and into the MIG gun torch. Once the wire touches the metal, an arc forms, which melts the wire and base metal. So, unlike TIG, the electrode becomes the part of the joint, and welding without a filler metal is impossible. 

MIG welding also creates spatter because the arc extinguishes and re-ignites every time the wire touches the metal. This occurs many times in a second during a typical short circuit MIG transfer. As a result, MIG welding inherently can’t make aesthetically pleasing welds like the TIG welding process.

However, since filler metal addition to the weld pool is automated, the MIG welding process is far easier to learn. Plus, you can achieve much higher welding speed and improve your productivity compared to TIG welding. 

If you can use the MIG welding process, do so because it’s more productive. You should use TIG welding when the joint quality is paramount, when welding exotic materials, or if weld aesthetics are essential.

Related: TIG vs MIG Welding – Main Differences

What Do I Need to TIG Weld?

TIG welding equipment is more expensive than MIG or stick welding gear. There are affordable TIG welders on the market, but they don’t offer all of the previously discussed functions for arc control.

The necessary equipment for TIG welding includes:

  • TIG welder – the most expensive piece of the setup. The TIG welding machine must support AC TIG output to weld aluminum.
  • Tungsten electrode – lanthanum, cerium, thorium, and pure tungsten rods are most commonly used. Thoriated tungsten is radioactive, but lanthanum is an excellent, safe substitute.
  • Filler rods – use ER70S-6 for general mild steel, ER308 for standard 200 and 300-series stainless steels, and ER4043 for most aluminum applications.
  • Shielding gas tank – Buy and refill, don’t rent. It’s cheaper that way. Read our guide on shielding gas tank sizes here, or just get an 80CF argon gas bottle that works great for most jobs and workloads.
  • Welding helmet – The hood should be rated for low TIG amperage if welding thin materials that require a low amp start.
  • Gloves – don’t use heavy-duty gloves for MIG or stick welding. Use light, flexible goatskin gloves designed for TIG.
  • Foot pedal – it allows you to moderate the amperage output in real-time, but not all welding machines support foot pedal connection.

You also need to arm yourself with patience. Learning how to TIG weld takes practice, lots of time, and hands-on experience. Don’t be discouraged if you fail to recreate those pristine welds posted by popular social media welders.

No one ever truly masters TIG welding. We are all just along for the ride. Ask any professional, and they’ll all say they are still learning.

But, with some practice, you’ll make beautiful, consistent welds in a flat, horizontal position. As you gain more experience, you’ll be able to weld more complex joints and work on exotic materials.

Pros and Cons of TIG Welding

Advantages of GTAW:

  • Maximum joint quality
  • Welds almost all materials
  • Perfect for thin stock
  • Low chance of weld contamination
  • Weld with or without filler metal
  • No spatter or smoke
  • It doesn’t require flux or slag
  • Allows welding in all positions
  • Maximum control over arc and heat input
  • Provides excellent visibility of arc and weld pool
  • TIG makes the best-looking welds

Disadvantages of GTAW:

  • It’s a challenging process to learn
  • TIG welding is a slow process, which reduces productivity
  • Small mistakes in travel speed, amperage output, pulse settings, or tungsten preparation can significantly impair weld quality
  • Welding outdoors blows away the shielding gas
  • Expensive equipment

Careers in TIG Welding

The best jobs for skilled TIG welders are in the aerospace and pipeline industries. However, pipeline work is often performed in harsh environments. So, if you can repair airplanes, you’ll have better working conditions.

Other industries include fabrication, structural welding, food and beverage, and oil and gas. All of these require skilled TIG operators to join exotic alloys and make complex joints. To get a high-paid TIG welding job, you’ll need to be a certified TIG welder. 

We recommend joining a welding school like Tulsa, Lincoln Electric, or Hobart. Not only will you learn from the best, but your welding instructors and career counselors can help you land a good job as soon as you get your papers. 

Wrapping It

TIG welding is the best arc welding method for achieving high-quality, beautiful welds. Thanks to a non-consumable electrode that precisely directs the arc and the numerous functions modern TIG equipment offers, you can tailor the arc and heat input exactly as needed.

However, TIG welding is slow and extremely hard to learn. For that reason, MIG welding is the most widely used arc welding process. But, GTAW is the reigning king in aesthetics and cleanliness, making it irreplaceable for many welding applications.

Also Read: 4 Main Types of Welding Processes

More TIG Welding Guides


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About Jeff Grill

Jeff Grill hails from Long Island, a 118 mile stretch of land that starts just off the coast of Manhattan and stretches deep into the Atlantic ocean. He has always been interested in welding from an early age and has the cuts and bruises to prove it as he set out to work with a variety of metals.


1 thought on “What is TIG Welding (GTAW) & How it Works”

  1. Hi
    Can you reccomend suitable Flux for 90/10 CuNi alloy A-TIG welding?
    Also optimal welding parameters sucu as current rate, voltage,gas flow,etc
    For 10 mm thickness 90/10 CuNi alloy plates.
    Best Regards

    Reply

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