TIG welding, or Gas Tungsten Arc Welding (GTAW), uses a non-consumable tungsten electrode to melt and bind metals with the aid of an inert shielding gas to prevent contamination. The process requires heat, shielding, and filler metal, with a focus on precise control and cleanliness, making it suitable for welding thin sections of various metals. While it produces high-quality welds, it is slower and more expensive compared to other welding processes.

1. TIG Welding
(GTAW)

2. Terms
• TIG stands for Tungsten Inert Gas
• Technically called Gas Tungsten Arc Welding or
GTAW

3. Arc Welding
• Process that is used to join metal to metal by using
electricity to create enough heat to melt metal.
• Melted metals when cool result in a binding of the
metals

4. Flux And Shielding Gas
• To protect the weld area from oxygen, and water
vapour.
• Depending on the materials being welded, these
atmospheric gases can reduce the quality of the
weld or make the welding more difficult.
• Improper gas can cause porous and weak weld.

5. TIG Welding
• Arc welding Process that uses a non-consumable
tungsten electrode to produce the weld.
• Weld area is protected from atmospheric
contamination by an inert shielding gas.
• A filler metal is normally used.

7. TIG Welding Requirements
• Requires 3 things, Heat, Shielding, and Filler metal.
• Heat is produced by electricity passing through the
tungsten electrode by creating an arc to the metal.
• The shielding comes from a compressed bottle of gas.
• The filler metal is just a wire that is dipped by hand into
the arc and melted

9. Process
• The welder turns on the gas flow by a valve on the TIG
torch.
• The torch is held over the weld joint just far enough for
the torch not to touch the metal.
• Then the welder presses a foot pedal and the TIG
torches tungsten electrode starts an arc.
• Once the arc is started the two pieces of metal begin to
melt by creating a puddle of metal.
• Once the puddle is established the welder with the
other hand starts filling the joint by manually dipping a
welding wire into the arc to fill the joint.

12. Components Of TIG Welder
• Main TIG welder components are,
• TIG Power Supply
• TIG Torch
• Shielding gas

13. TIG Power Supply
• Usually welding power supplies which supplies
constant current.
• “High frequency start” eliminates the need to
physically strike an arc like SMAW by creating a
brief moment of high voltage.
• Pre-flow and post-flow feature confirms the
protection of the weld by supplying shielding gas
before and after the weld is performed.
• Frequency settings help the characteristics of the
welding arc.

14. TIG Welding Voltage Type and
Welding Polarities
• Both AC and DC currents are used.
• D/C electrode (-) negative concentrates about 2/3
of the heat onto the metal welded.
• This produces a deep penetration weld.
• D/C electrode (+) positive concentrates about 2/3
of the heat onto the electrode.
• This produces a shallow weld.

15. TIG Torch
• Torch consists various electrodes, cups, collets and
gas diffusers.
• Basic torch types are
• Air cooled torch which is least expensive
• Water cooled torch which is most efficient.
• As the name main ingredient is tungsten in the
electrode.
• Pure tungsten
• Zirconium Tungsten
• Thorium tungsten

17. Tungsten Electrode
• Create the arc for TIG welding.
• Tungsten properties allows an arc to maintain a
temp up to 11 000oF.
• Electrode diameter is vary 1/16 to ¼ of an inch.
• Most critical component of the process is shape of
the tip of the electrode.
• Pointed tip – welding ferrous metals.
• Rounded and Tapered ball end – welding non-ferrous
metals.

18. Shielding Gas
• Necessary to protect welding area from
atmospheric gases which can cause fusion defects,
porosity and weld metal embrittlement.
• Also transfers heat from the tungsten electrode and
helps start and maintain a stable arc.
• Most of cases pure Argon is used.
• Argon-Hydrogen, Argon-Nitrogen, Argon-Helium
mixtures are also used.
• Ar-He typically used on thicker metals to get deep
penetration.

20. USES
• Most commonly used to weld thin sections of
stainless steel, steel and non-ferrous metals such as
Aluminum, Copper Nickel alloys, Magnesium,
Titanium.
• Combinations of dissimilar metals also TIG welded
such as Copper to Everdur, Copper to Stainless
Steel, Nickel to steel and Stainless Steel to Cast
iron.

21. Advantages
• Works on almost all types of metals with higher
melting points. Specially for reactive metals like
titanium and zirconium, which dissolve oxygen and
nitrogen and become embrittled.
• Accuracy and control. The process provides more
precise control of the weld than any other arc
welding process, because the arc heat and filler
metal are independently controlled.
• Good looking weld beads
• Very good for joining thin base metals because of
excellent control of heat input.

22. • Creates strong joints. It produces top quality welds
in almost all metals and alloys used by industry.
• Clean process with minimal amount of of fumes,
sparks, spatter and smoke i.e. minimal finishing
required.
• Works in any position.
• Because the electrode is non-consumable, the
process can be used to weld by fusion alone
without the addition of filler metal.

23. Disadvantages
• Brighter UV rays when compared to other welding
processes
• Slower process than consumable electrode arc
welding processes.
• Takes practice (Difficult Process)
• More expensive process overall. Expensive welding
supplies (tungsten Electrodes and Shielding gases)

24. • Not easily portable.
• Transfer of molten tungsten from the electrode to
the weld causes contamination. The resulting
tungsten inclusion is hard and brittle.
• Exposure of the hot filler rod to air using improper
welding techniques causes weld metal
contamination.