Tungsten Inert Gas welding (TIG) also referred as Gas Tungsten Arc Welding (GTAW) is among the most popular welding processes. The technique was popularized in the 1940s after being successfully used to join magnesium and aluminum successfully. Since then, TIG has continued to play a crucial role in the acceptance of aluminum for welding and structural application. Here we are going to give you a guide to TIG welding.
TIG welding is popular because of its versatility, cleaner welds and minimal requirement for finishes, and suitability with different metals. Although it’s not the cheapest or easiest welding technique to master, the results achieved using TIG are an amazing reward for the effort.
What is Tungsten Inert Gas Welding?
Tungsten intert gas (TIG) welding is a fusion welding process that produces a weld with a non-consumable tungsten electrode.
The process uses heat generated, but an electric arc is usually struck between a non-consumable tungsten electrode and the material being welded to produce a molten weld pool.
TIG welding is suitable for These Metals
- steel
- aluminum
- stainless steel
- chromoly
- copper
- brass
- bronze
- nickel alloys
- magnesium
- titanium
Guide to TIG Welding How does it Work
TIG welding utilizes current supplied using a tungsten electrode, which creates an arc (short circuit) between the temperature resistant electrode and the material being welded. The arc heats up and liquefies the material, but there is a nozzle that shields the material from a chemical reaction with the air.
The main gases used in the nozzle are argon, helium, or a mix of both, as they are non-reactive. These gases prevent chemical reactions between the weld pool molten material and air. It also allows for precision, resulting in high-quality weld seams.
The process may be undertaken with or without a filler. Since the tungsten electrode is non-consumable, the filler can be added by hand or using a consumable wire or rod that’s fed to the weld pool.
TIG Welding Power Source
TIG welding requires a constant supply of current power sources to prevent excessively high currents from being drawn during the emission of an arc on the work metal. This can happen while starting the process or during welding.
If a flat characteristic power source is used, any contact created with the work piece surface will damage the electrode tip. The electrode can also be fused to the work surface.
TIG Arc Starting
The TIG welding arc can be started by scratching the surface, therefore forming a short circuit. However, the current will only start flowing once the short circuit is broken.
However, with this process, there is a risk of the electrode sticking to the surface of the material being welded. The lift arc technique can be employed to minimize the risk through the formation of a short circuit at a very low current.
Another popular way of starting TIG welding is by the use of high frequency, which consists of high voltage sparks lasting for milliseconds. These sparks will cause ionization of the electrode and work surface gap, and once formed, current begins to flow from the power source.
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Gases used for TIG Welding
The most common gases used in the process include;
Argon– this is the most used gas as it can be used for various materials such as aluminum, stainless steel, and titanium.
Helium and Helium argon mixes– combining helium and argon raises the temperature of the arc to increase the welding speed and deepen the weld penetration. The disadvantage of this is the high cost of the gas and difficulty in starting the weld.
Argon and hydrogen 2%-5%- this involves the addition of hydrogen and argon for cleaner-looking welds as the mix reduces surface oxidation. The arc produced with the mix is hotter, therefore, promoting higher welding speeds. The disadvantage of this mix is it can cause the cracking of carbon steel.
TIG Welding Applications
The most common applications of TIG welding are in the pipeline and pipe welding projects. It is also used in chemical plants, aviation, and aerospace industries. It’s also common in steel industries when welding thin materials such as titanium.
What are the advantages and disadvantages of TIG Welding?
Advantages of TIG Welding
1/ Various applications
TIG welding can be used for various materials and applications, including industrial equipment, vehicles, furnishings, and more. It can also be used with various positions, such as vertical and horizontal.
2/ Precision
The process promotes detailed precision by controlling the temperature to ensure less spattering. The arc is transparent due to the use of inert gases enabling the welder to clearly observe the work.
3/Temperature resistant electrodes
There’s no need to continuously replace the electrode when using TIG welding as it’s non-consumable. The technique produces cleaner joints each time.
4/ Versatility
Welding can be done with or without filler metal, and where a filler is necessary, it must be added separately to the weld pool.
5/Complex Metal welding
TIG welding can be used for materials that require a high melting point. It can be used on metals such as aluminum, copper alloys, titanium, and gold.
6/ Ductility
TIG welds are extremely ductile, making them less brittle, strong, and corrosion resistant.
Disadvantages of TIG Welding
1/Time-consuming
TIG welding is a slow process that requires the welder to take their time to get the work done. The welding machine is generally slower than other welding processes.
2/ Steeper learning curve
TIG welding is quite a complex process that requires a lot of practice. It takes longer to master, but as we keep saying, the rewards for mastering TIG welding are amazing.
3/ High Cost of inert gases
Inert gases used by the TIG welding machine are more expensive than what’s used in other welding processes. The welding machine also requires frequent cleaning and maintenance to guarantee prolonged use.
What are the limitations to TIG welding?
Although TIG welding is a simple process once you have mastered the skill, it comes with various limitations.
- It requires high skill mastery. The skill takes a longer time to master.
- It’s not recommended for thick metals.
- It requires a clean working surface for the best results.
- It’s not suitable for working in an open or outdoor welding space due to wind.
- The travel speed and depositing rates are quite low, increasing the cost of welding.
- It’s not easy to automate
- It raises safety issues as welders are exposed to high intensity of light
Guide to TIG Welding Conclusion
TIG welding is the go-to welding process for clean welds where high level accuracy is needed. The skill takes time to master, but you will enjoy the rewards. TIG welding can be used for a wide variety of metals and can handle the trickiest welds such as s-shapes, corners, and curves. TIG welding requires practice and patience for the best results.
