Summary
Tungsten inert gas welding (TIG) also referred to as gas tungsten arc welding uses an electric arc that is struck between a non-consumable tungsten alloy electrode and the metal workpiece to be welded. The non-consumable tungsten electrode delivers the current to the welding arc.
An inert gas such as argon is used to protect and cool the tungsten and weld puddle. This welding process is precise and versatile and is used to produce high-quality welds and protect the welding area from atmospheric contamination with an inert gas such as argon.
TIG welding is widely used in the aerospace industry, used on thin materials especially non-ferrous metals and also thin wall tubing material.
The major parts of tungsten inert gas welding include AC or DC power supply, non-consumable tungsten electrode, inert gas supply, and welding head. Learn about Plasma Arc Welding here!
Now, let’s go deep to explain what tungsten inert gas welding is, its applications, parts, diagram, working, advantages, and disadvantages! The difference between MIG and TIG will also be discussed!
Contents
What is TIG Welding?
Tungsten inert gas (TIG) welding is also known as gas tungsten inert arc welding (GTAW). It is an arc welding process that uses a non-consumable tungsten electrode.
The electrode is protected from atmospheric contamination or oxidation by an inert shielding gas (a mixture of argon or helium). Filler metal may be and may not be added for those autogenous welds.
Electrical energy transfers current through a Colum of highly ionized gas and metal vapors, which is known as plasma. This welding process became successful in the 1940s for joining aluminum and magnesium. It uses an inert gas shield to protect the weld, unlike other arc welding process that uses slag.
Applications of Tungsten Insert Gas (TIG) Welding
The followings are the applications of TIG welding:
- It is widely used in aerospace industries
- Industries use TIG welding on a thin workpiece, especially nonferrous metals
- It is used in the manufacturing of space vehicles
- TIG welding is suitable on small diameter, thin wall tubing, making it applicable in bicycle industries
- It is used to repair and manufacture works
- The process is used to repair tools and dies, especially ones made of aluminum and magnesium.
Some material applications of TIG welding include:
Stainless steel, alloy steel, aluminum, titanium, copper, magnesium, nickel alloys
Diagram of TIG welding
Tungsten inert gas welding Machine
TIG welding machine consists of the following component:
- AC or DC power supply
- Non-consumable tungsten electrode
- Inert gas supply
- Welding head
How Does TIG Welding Works?
The working of tungsten inert gas welding is less complex and can be easily understood. It operates under a similar principle to MIG welding; the base metal and bonding materials are melted by the heat generated by an electrical current. it then cools and forms a solid joint. Although there is still a huge difference between the welding despite the similarities.
Watch the video below to learn the working of gas tungsten arc welding (GTAW):
Differences between MIG and TIG welding
The table below shows the difference between TIG and MIG welding:
| MIG Welding | TIG Welding |
|---|---|
| Metal inert gas (MIG) welding utilizes a consumable electrode that is continuously fed into the welding zone from a wire pool. | Tungsten inert gas (TIG) welding utilizes a non-consumable electrode (so it remains static and intact during welding). |
| The electrode itself melts down to supply the necessary filler metal required to fill the root gap between base metals. So electrode acts as filler metal (no additional filler is required). | If required, the filler metal is supplied additionally by feeding a small diameter filler rod into the arc. So filler metal is supplied separately. |
| The composition of electrode metal is selected based on the parent metal. Usually, the metallurgical composition of electrode metal is similar to that of base metal. | An electrode is always made of tungsten with a small proportion of other alloying elements (like thorium). |
| It is suitable for homogeneous welding. It cannot be carried out in autogenous mode welding as filler is applied inherently. | It is particularly suitable for autogenous mode welding. However, it can also be employed for homogeneous or heterogeneous modes by supplying additional filler. |
| The electrode-cum-filler for MIG welding comes in the form of a small diameter (0.5 – 2 mm) and very long (several hundred meters) wire that is wound in a wire pool. | TIG welding filler typically comes in the form of a small diameter (1 – 3 mm) and short length (60 – 180 mm) rod. |
| Due to its very large length, the filler electrode can be fed for a longer duration without replacement. | Due to the short length, frequent replacement of filler is required. This interrupts the welding process unintentionally. |
| MIG welding is commonly carried out either in AC or in DCEP polarity so that electrodes can be melted and deposited at a faster rate. | TIG welding is commonly carried out either in AC or DCEN polarity to increase electrode life. |
| The filler deposition rate is very high, so the process is highly productive. | The filler deposition rate is low. In this sense, it is not very productive. |
| MIG welding usually produces a spatter. This causes the loss of costly filler metal. | TIG welding is mostly free from spatter. |
| The quality and appearance of weld beads are not very good. | It can easily produce defect-free reliable joints with a good appearance. |
| It does not lead to a tungsten inclusion defect. | TIG welding sometimes leads to a tungsten inclusion defect (occurred when a melted/broken part of the tungsten electrode gets embedded into the weld bead). |
Advantages of TIG Welding
Below are the benefits of TIG welding:
- It produces high-quality welds
- It is protected by the inert gas during the process
- TIG welding does not produce slag
- It can be performed in any welding position
Disadvantages of TIG Welding
Below are the limitations of TIG welding:
- Offers a slow welding process
- High-skilled labor is needed
- Operation cost is much more expensive
- Welder’s exposure to high intensities of light
Learn about Submerged Arc Welding here!
That is all for this article, where I explained gas tungsten arc welding (GTAW), and tungsten inert gas welding (TIG). We also discussed the difference between MIG and TIG welding. I hope you got a lot from the reading, if so, kindly share it with other students. Thanks for reading, see you next time!