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EZITIG 180
electrodes today and are preferred for their longevity
and ease of use.
Thorium increases the electron emission qualities of
the electrode, which improves arc starts and allows
for a higher current-carrying capacity. This electrode
operates far below its melting temperature, which
results in a considerably lower rate of consumption
and eliminates arc wandering. Compared with other
electrodes, thoriated electrodes deposit less tungsten
into the weld puddle, so they cause less weld con-
tamination.
Thorium is a low-level radioactive hazard and many
users have switched to other alternatives. Thorium
is an alpha emitter but when enclosed in a tungsten
matrix, the risks are negligible. Thus holding a stick
of Thoriated tungsten in your hand should not pose
a great threat unless a welder has open cuts on their
skin. Thoriated tungsten should not get in contact
with open cuts or wounds. The more significant dan-
ger to welders can occur when thorium oxide gets
into the lungs. This can happen from the exposure to
vapours during welding or from ingestion of material/
dust in the grinding of the tungsten. Follow the manu-
facturer’s warnings, instructions, and the Safety Data
Sheet (SDS) for its use.
jagged edges, imperfections, or poor surface finishes
not visible to the eye that will contribute to weld in-
consistency and weld defects.
Always grind the tungsten in a longitudinal direc-
tion. Tungsten electrodes are manufactured with the
molecular structure of the grain running lengthwise
and thus grinding crosswise is “grinding against the
grain.” If electrodes are ground crosswise, the elec-
trons have to jump across the grinding marks and
the arc can start before the tip and wander. Grinding
longitudinally with the grain, the electrons flow stead-
ily and easily to the end of the tungsten tip. The arc
starts straight and remains narrow, concentrated, and
stable.
Tungsten Electrode Current Ranges
1.0mm
15 - 80
1.6mm
70 - 150
2.4mm
150 - 250
3.2mm
250 - 400
4.0mm
400 - 500
Tungsten
DC Current Amps Torch
Diameter
Negative 2% Thoriated
Tungsten Preparation
Always use DIAMOND wheels when grinding and
cutting. While tungsten is a very hard material, the
surface of a diamond wheel is harder, and this makes
for smooth grinding. Grinding without diamond
wheels, such as aluminium oxide wheels, can lead to
Grind longitudinal on the
grinding wheel
DO NOT grind across the
grinding wheel
Electrode Tip/Flat
The shape of the tungsten electrode tip is an impor-
tant process variable in precision arc welding. A good
selection of tip/flat size will balance the need for sev-
eral advantages. The bigger the flat, the more likely
arc wander will occur and the more difficult it will be
to arc start. Increasing the flat to the maximum level
that still allows arc start and eliminates arc wonder
will improve the weld penetration and increase the
electrode life. Some welders grind electrodes to a
sharp point, which makes arc starting easier but can
contribute to decreased welding performance due to
the tip me lting and falling into the weld pool.
2.5 x Tungsten Diameter
Flat
Tip
Pointed
Tip
Electrode Included Angle/Taper
DC Welding Tungsten electrodes for DC welding
should be ground longitudinally and concentrically
with diamond wheels to a specific included angle in
conjunction with the tip/flat preparation. Different an-
gles produce different arc shapes and offer different
weld penetration capabilities.
