Operators Manual
16
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TIG Welding (GTAW)
Connection for TIG Welding
For TIG Welding, the TIG torch is connected
to the negative terminal. Figure 7 illustrates
the correct connection of the welding torch
and gas supply. Welding grade Argon is the
shielding gas most commonly used for AC/
DC GTAW welding. The torch will require a
tungsten electrode.
Before first use of the welding torch,
allow gas to purge the torch and hoses for
1 minutes at approximately 10 litres/min. For
welding purposes, the gas flow rate should
be set in the range 5-11 litres/min.
Fig 7
Connections for TIG Welding
Electrode TIG
Thoriated Tungsten electrodes are normally
used for DC welding current, and Zirconiated
Tungsten electrodes are normally used for AC
TIG welding.
For AC TIG welding a Thoritated tungsten
(red tip) can be used for low current AC TIG
but the tip does not ball well and the arc can
then wander.
Ceriated or Lanthinated are preferred for
advanced AC Welding with square wave
output. They can also be used on DC TIG,
so they are a good AC or DC electrode if
only one electrode type is to be used.
Tungsten Electrode Preperation
The tungstens needs to be ground to a point,
the grinding should only be in the direction
of the point and should be done on a fine
grit grinding wheel. The resulting grind
pattern will produce a sharp directed arc.
Poor tip preparation will result in arc wander.
A common practice is to grind the tip such
that the length of the points is approximately
2 times the diameter. The result will be an
included angle of 30 degrees.
For AC tip preparation, creating a blunt end
will assist a symmetrical and small ball to
develop at the tip.
It is important to maintain the electrode
point for DC or ball for AC. If the tip
accidently touches weld pool it will become
contaminated and the arc will become
erratic, and will need to be re ground.
Tungstens containing at least 2% lanthana
will hold a point when used with both DC
and AC welding currents
7 Basic Welding Information
TIG
Torch
Work
Clamp
