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Electrode Included Angle/Taper - DC Welding
Tungsten electrodes for DC welding should be ground longitudinally and concentrically with diamond wheels to a specic
included angle in conjunction with the tip/at preparation. Dierent angles produce dierent arc shapes and oer dierent
weld penetration capabilities. In general, blunter electrodes that have a larger included angle provide the following ben-
ets:
• Last Longer
• Have better weld penetration
• Have a narrower arc shape
• Can handle more amperage without eroding.
Sharper electrodes with smaller included angle provide:
• Oer less arc weld
• Have a wider arc
• Have a more consistent arc
The included angle determines weld bead shape and size. Generally, as the included angle increases, penetration increases
and bead width decreases.
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 jagged edges, imperfections, or poor surface nishes not visible to the eye that will contribute to weld inconsistency
and weld defects.
Always ensure to grind the tungsten in a longitudinal direction on the grinding wheel. 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 electrons have to jump across the grinding marks and the arc can start before the tip and
wander. Grinding longitudinally with the grain, the electrons ow steadily and easily to the end of the tungsten tip. The arc
starts straight and remains narrow, concentrated, and stable.
grind longitudinal on the
grinding wheel
don’t grind across
the grinding wheel
at tip
2.5 times tungsten diameter
pointed tip
Electrode Tip/Flat
The shape of the tungsten electrode tip is an important process variable in precision arc welding. A good selection of tip/
at size will balance the need for several advantages. The bigger the at, the more likely arc wander will occur and the more
dicult it will be to arc start. However, increasing the at 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 still grind electrodes to a sharp point,
which makes arc starting easier. However, they risk decreased welding performance from melting at the tip and the possibility
of the point falling o into the weld pool.
at spot diameter
included angle
Tungsten Diameter at Constant Included Current Range Current Range
Diameter the Tip - mm Angle - Degrees Amps Pulsed Amps
3/64” (0.040”) .250 20 05 - 30 05 - 60
1/16” (.062” & .060”) .500 25 08 - 50 05 - 100
1/16” (.062” & .060”) .800 30 10 - 70 10 - 140
3/32” (.93”) .800 35 12 - 90 12 - 180
3/32” (.93”) 1.100 45 15 - 150 15 - 250
1/8” (.125”) 1.100 60 20 - 200 20 - 300
1/8” (.125”) 1.500 90 25 - 250 25 - 350
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