What is TIG Welding Process or Gas Tungsten Arc Welding (GTAW)

In TIG Welding Process, TIG stands for Tungsten Inert Gas. TIG is also known as Gas Tungsten Arc Welding (GTAW). It is a process which uses a non consumable tungsten electrode to form the weld. Generally it uses filler metal but in some autogenous weld it does not require it. To protect the weld area from atmospheric contamination, helium or argon is used as a shielding gas. A constant current welding power supply is used to produce the arc in between the electrode and workpiece.
 
What is TIG Welding Process or Gas Tungsten Arc Welding
 
 
Try to answer these questions by yourself.
 
1. What TIG and GTAW stands for?
2. Which type of electrode is used in TIG welding process?
3. Name the shielding gas which is used to protect the weld from atmospheric contamination.
4. What type of welding power supply is used to produce the arc?
 
Most commonly TIG or Gas Tungsten Arc Welding (GTAW) is used to weld thin sections of stainless steel, magnesium, aluminum and copper alloys. But it can weld all types of metals. This welding process allows operator a better control over the weld as compared with Shielded Metal Arc Welding (SMAW) and Gas Metal Arc Welding (GMAW). It is a complex welding process and not easy to master. It requires a lot of hard work and practice to master.

Working Principle

In TIG Welding process, an arc is produced in between the non consumable tungsten electrode and workpiece which is to be joined. The arc so produced creates an intense heat which melts the two metal pieces and fuses them together to form a strong weld by the use of a filler metal. The weld so formed exhibits the similar properties that of the base metal. A shielding gas environment is used to prevent the weld from atmospheric contaminations.

Main Equipment

The main equipment used in TIG welding process is:
1. Welding torch
2. Non consumable tungsten electrode
3. A constant current welding power supply
4. A shielding gas ( helium of argon) source

Working

What is TIG Welding Process or Gas Tungsten Arc Welding
 
  • In TIG welding process or Gas Tungsten Arc Welding , the welding torch is connected to a constant current welding power supply and shielding gas source.
  • With the help of the constant current supply, electric arc is produced in between the electrode and two metal workpiece which are to be joined.
  • A filler metal is used join the two metal pieces together. As the spark is struck, the filler metal is inserted in the cavity, and due to intense heat, the filler metal melts and fill the cavity between the two metal pieces and forms a strong weld.
  • A shielding gas (He or Ar) is used to protect the weld from atmospheric contaminations. As the arc is produced, simultaneously the shielding gas also starts to spread near the weld area and avoids the weld to combine with atmospheric air and protect it from contaminations.
  • The welding is performed by a high skilled operator. The operator has better control over the weld. He can use his both hands to control heat generated and filler metal. From one hand he controls the arc produced and with other hand he controls the feed of filler metal.
Watch the video for better explanation of what is TIG welding process or Gas Tungsten Arc welding.
 
 

Application

The TIG welding process is used in aerospace industries, used to weld thin metal sheets, especially non-ferrous metals. It is used to manufacture of space vehicles, in bicycle industries to weld small diameter and thin wall tubing. It is often used to make root or first-pass weld for piping of various sizes. It is used in maintenance and repair work.

Advantages and Disadvantages

The various advantages and disadvantages of GTAW or TIG welding process are as follows

Advantages

  • Almost all metals cab be welded by this technique. But most commonly it is used to weld stainless steel, Al, Mg and Cu alloys.
  • It allows better control over the weld. This is because operator uses both the hand to perform the operation, one hand to control the arc and other to control the feed of filler metal.
  • The welds formed are highly resistance to corrosion.
  • Welds thin metal sheets.
  • Produces good quality welds with precision.
  • It is a clean process because of less emission of fumes, sparks, spatter and smoke.
  • It is suitable for work in any position.
  • It offers greater visibility during the operation due to less emission of smoke and fumes.

Disadvantages

  • It is a complex process and difficult to master.
  • It is not portable and hence suitable for welding shops only.
  • It is slower welding process as compared with other welding processes.
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