Tungsten Inert Gas Welding: Construction, Working Principle, Applications, Advantages, and Disadvantages [With PDF]

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Tungsten inert gas (TIG) welding is a type of arc welding that uses tungsten as an electrode and the electrode is non-consumable in nature. This welding is also known as Gas tungsten arc welding (GTAW).

Today in this paper we will see the Definition, Main parts or Equipment, Working Principle, Advantages, Disadvantages, and Applications of Tungsten Inert Gas Welding.

So Let’s start with the Definition first.

What is Tungsten Inert Gas Welding?

Tungsten inert gas (TIG) welding is one type of arc welding method where we use a non-consumable tungsten electrode, to weld the two metallic bodies. The weld spot is protected from contamination by helium, argon and other inert shielding gases.

With this process, there is no longer a need for filler metal that is typically used in the process of arc welding. This process makes this kind of weld highly resistant to the effects of corrosion.

Construction of Tungsten Inert Gas Welding Machine:

A Tungsten Inert Gas Welding Machine consists of the following equipment:

  • Power Supply
  • Inert Gas Supply
  • Welding Torch/Holder
  • Tungsten Electrode
  • Shielding Gas
  • Filler Rod
parts of tig welding
Main Parts of Tungsten Inert Gas Welding Machine, Learn Mechanical

Power Supply:

In TIG welding we need a constant power supply because if there was a fluctuation of current then it is hard for the welder to weld the joints properly.

The power supply can be two types:

  1. DC Power Supply
  2. AC Power Supply

In the DC power supply, we can weld steels, nickel, titanium, etc. And in AC power supply, we can weld magnesium, aluminum, etc. materials.

image of Tig welding power supply unit
Power Supply Unit of TIG Welding

Inert Gas Supply:

In TIG Welding, we need an inert gas supply to provide the shielding to the weld area from the atmospheric gas (For example, Oxygen, Nitrogen, and Hydrogen).

In general, Argon is used as an Inert gas supply in TIG Welding. We will discuss this later on the Shielding gas section.

Argon gas cylinders
Argon Gas Cylinders

Welding Torch:

In TIG Welding the welding torch is designed to do either automatic and manual operations. However, in terms of construction, both are the same, in the manual torch, they are provided with a handle to hold, and in case of automatic, they are designed to mount on an automatic machine.

Torches are provided with a cooling system either by water or air.

When the Ampere of the current is less than 200 A generally we use air-cooling, but if it exceeds 200 A than we use water cooling to decrease the temperature of the welding torch.

The inside portion of the welding torch is generally made of copper to increase the conductivity of heat.

And the torches are provided with a holding arrangement (Port) to hold the Tungsten electrode firmly.

image of welding torch
Parts of Welding Torch

Tungsten Electrode:

In TIG Welding we use a non-consumable electrode made of Tungsten or Tungsten Alloy.

Due to High-temperature resisting capacity (Melting Temp of Tungsten is 3,422 °C ) of tungsten rather than any other metal, that’s why we use the tungsten electrode.

The diameter of the electrode is generally varies from 0.5 mm to 0.65 mm, and the length varies between 75 mm to 610 mm.

Image of Tungsten Electrode
Bunch of tungsten Eletrode

Shielding Gas:

Shielding gases are used to protect the welding pool from atmospheric gases like nitrogen, oxygen otherwise these gases can damage the welding surface by creating porosity, blowhole, etc.

Choosing of Shielding gases depends on the types of welding as well as the atmospheric condition along with the type of metal used for the operation and many more.

However, generally, we use Argon as a shielding gas in TIG Welding. Sometimes Argon-helium mixtures are also used in this type of welding.

Filler Rod:

As we already know, in TIG Welding, we use a non-consumable electrode that is Tungsten, so in some cases, we need separate material to fillup the gap between two joints.

The material of the filler rod can be anything, like carbon steel, aluminium, etc. It generally depends on the type of joints, the work-piece material, thickness and also the properties of the workpiece.

bunch of filler rods
A Bunch of Filler Rods

Working Principle of Tungsten Inert Gas Welding:

When we switch on the machine the high-frequency generator provides an electric spark.

The electric spark is struck between the Workpiece and the Electrode either by touching electrode by scrap material or by using a high-frequency unit.

We need to do this operation (Touching with the scrap material) at least 2-3 times to warm up the electrode before the actual operation started. Due to this, we can save the breaking of the electrode tip.

In actual operation, the heat generated by the electric spark which fuses the metal from the joint area and it produce a molten weld pool. The size of the pool depends on the size of the electrode and the amount of the current supplied by the generator.

The arc area is surrounded by an inert or reducing gas shield to protect the weld pool and the non-consumable electrode.

The process may be operated autogenously, that means without filler material or filler material may be added by feeding a consumable wire or rod into the established weld pool.

Tungsten Inert Gas Welding produces very high-quality welds across a wide range of materials with thicknesses up to about 8 or 10mm.

Let us quickly watch a actual video of TIG Welding Process:

Applications of TIG Welding:

This is specially used in the welding of refractory, sheet, and reactive materials.

Tungsten Gas welding can be used with such a large variety of metals, the process can be applied to several industries and aid in the creation and repair of many items. This form of welding is common in the aerospace, automotive, repair, and art fields.

  • Aerospace: Aircraft and spacecraft are constructed in part by means of TIG welding.
  • Automotive: Safe and secure construction is essential in the auto industry, as is making vehicles stand the test of time.
  • Repair: TIG may be used in a number of repair applications. From fixing a child’s toy, like a wagon or old-fashioned pedal car, to repairing aluminum tools, this welding method comes in handy.

Advantages of TIG Welding:

The advantages of Tungsten Inert Gas Welding are the following:

  • Tungsten welding offers a solution for welding critical joints, and for situations where small or exceptionally precise welds are required.
  • It can be performed with a wide variety of metals
  • And, when done correctly, it produces a high-quality and high-purity weld compared with other joining processes, which is crucial in many applications.
  • It can be done in both automatic and manual. 
  • Overall, it is one of the most efficient ways to join two metals.
  • No slag is produced.
  • TIG Welding can be done in any position.

Disadvantages of TIG Welding:

The disadvantages of TIG Welding are mentioned below:

  • Tungsten welding can not be used for thicker sheets of metals.
  • More complicated-High Skilled and professional workers are needed.
  • The safety issue, welders are exposed to the high intensity of lights which can cause eye damage.
  • The price of TIG welding services is high. However, costs will vary depending upon the materials being welded, and the scope of the project.
  • It is a slow process welding.

So this is all about Tungsten Inert Gas Welding, I hope you enjoyed this article. I also wrote articles on some other welding processes do check out those too and moreover do not forget to share the article on your favourite social platform.

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