Jasic EVOLVE 200 Operator's Manual page 51

GUIDE TO TIG WELDING
Before starting any welding activity ensure that you have suitable eye protection and
protective clothing. Also take the necessary steps to protect any persons within the welding
area.
TIG welding electrodes
TIG welding electrodes are a 'non consumable' as it is not melted into the weld pool
and great care should be taken not to let the electrode contact the welding pool to
avoid weld contamination. This would be referred to as tungsten inclusion and may
result in weld failure.
Electrodes will often contain small quantities of metallic oxides which can offer the
following benefits:
• Assist in arc starting
• Improve current carrying capacity of the electrode
• Reduce the risk of weld contamination
• Increase electrode life
• Increase arc stability
Oxides used are primarily zirconium, thorium, lanthanum or cerium. These are added
usually 1% ~ 4%.
Tungsten Electrode Colour Chart - DC
Welding Mode
DC or AC/DC
DC or AC/DC
DC or AC/DC
DC or AC/DC
DC
DC
Tungsten electrode preparation - DC
When welding at low current the
electrode can be ground to a point.
At higher current a small flat on the end
of the electrode is preferable as this helps
with arc stability.
Electrode grinding
It is important when grinding the electrode to take all necessary precautions such as wearing eye
protection and ensuring adequate protection against breathing in any grinding dust.
Tungsten Type
Ceriated 2%
Lanthanated 1%
Lanthanated 1.5%
Lanthanated 2%
Thoriated 1%
Thoriated 2%
Colour Tungsten Electrode Size
Grey
Black
Gold
Blue
Yellow
Red
Tungsten electrodes should always be ground lengthwise
(as shown left) and not in a radial operation.
Electrodes ground in a radial operation tend to contribute
to arc wander due to the arc transfer from the grinding
pattern. Always use a grinder solely for grinding
electrodes to avoid contamination.
51
Tungsten Electrode Current Ranges
1.0mm
1.6mm
2.4mm
3.2mm
4.0mm
4.8mm
DC Current Amp
30 - 60
60 - 115
100 - 165
135 - 200
190 - 280
250 - 340