What is TIG Welding?

TIG Welding, more technically known as Gas Tungsten Arc Welding (GTAW), employs an AC/DC machine with a flow of shielding gas. It welds by using a non-consumable tungsten rod to establish an arc on the workpiece. The arc melts the base metal and creates a weld pool. Additionally, a filler metal rod may be applied manually by hand when required. The shielding gas protects the weld from contaminants.

How is it used?

TIG is more appropriate for thin and small materials, since the TIG torch uses a low amperage. TIG is also sought after when high quality, aesthetically appealing, precise welds are required. The most important applications for TIG welding are pipeline and pipe welding. It is, however, used in many industries, such as aviation and aerospace and sheet metal industries when welding particularly thin materials and special materials such as titanium. TIG welding is suitable for both manual and mechanized welding as well.

 

Tungsten Electrode
 

The tungsten electrode is the core of TIG welding. Tungsten has the highest melting point of all pure metals in the periodic system, at 3380 degrees Celsius. This allows the electrode to remain solid when it emits an arc that heats and liquefies the workpiece material. The electrodes can be alloyed with oxidic additives, and they are color-coded according to the alloy, they are available in 8 or more alloys/colours, with each of their unique weld properties and purposes.

Advantages

  • Superior high quality welds. TIG offers greater arc and weld puddle control as the heat input is often controlled by pressing on a foot pedal. Heating or cooling down the weld puddle allows for precise weld bead control, making the TIG method ideal for cosmetic welds like sculptures and automotive welds.
  • Clean weld. Provided that the workpiece metal is clean, TIG welding does not produce sparks or spatter. It also does not require flux, and does not produce slag. In addition, the process does not produce smokes or fumes, unless the welded metal contains comtaminants.
  • Suitable for all weld positions and able to weld in tight confined areas.

Disadvantages

  • Can only be welded on clean, non-contaminated metals. As using the TIG method to weld unclean metals will result in a considerably weak weld.
  • Slower welding process, as TIG welding has a lower deposition rate.
  • Requires high degree of skill and effort. TIG welding employs the use of both hands, one for the torch containing the tungsten rod, one for the metal filler rod. The welder also uses his feet to control the foot pedal.
  • Produces twice the amount of infrared and UV rays compared to normal welding.