One of the welding processes that used in Engineering field is the TIG welding. There are several types of welding processes similar to this, but tig welding has its unique features. Thanks for the colleagues who give this slides to publish.

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.