27
Tungsten being oxidised after
weld is finished
Keep shielding gas flowing 10–15
seconds after arc stoppage. 1 second
for each 10amps of weld current.
2
Contaminated
tungsten
Touching tungsten into the weld
pool
Keep tungsten from contacting weld
puddle. Raise the torch so that the
tungsten is off of the work piece 2 -
5mm
Touching the filler wire to the
tungsten
Keep the filler wire from touching the
tungsten during welding, feed the filler
wire into the leading edge of the weld
pool in front of the tungsten
3
Porosity - poor weld
appearance and
colour
Wrong gas / poor gas flow /gas
leak
Use pure argon. Gas is connected,
check hoses, gas valve and torch are
not restricted. Set the gas flow
between 6-12 l/min. Check hoses and
fittings for holes, leaks et
Contaminated base metal
Remove moisture and materials like
paint, grease, oil, and dirt from base
metal
Contaminated filler wire
Remove all grease, oil, or moisture
from filler metal
Incorrect filler wire
Check the filler wire and change if
necessary
4
Yellowish residue /
smoke on the alumina
nozzle & discoloured
tungsten
Incorrect Gas
Use pure Argon gas
Inadequate gas flow
Set the gas flow between 10 - 15 l/min
flow rate
Alumina gas nozzle too small
Increase the size of the alumina gas
nozzle
5
Unstable Arc during
DC welding
Torch connected to DC +
Connect the torch to the DC- output
terminal
Contaminated base metal
Remove materials like paint, grease, oil,
and dirt, including mill scale from base
metal.
Tungsten is contaminated
Remove 10mm of contaminated
tungsten and re grind the tungsten
Arc length too long
Lower torch so that the tungsten is off
of the work piece 2 - 5mm
6
Arc wanders during DC
welding
Poor gas flow
Check and set the gas flow between 10
- 15 l/min flow rate
Incorrect arc length
Lower torch so that the tungsten is off
of the work piece 2 - 5mm
