IS TUNGSTEN GRIND ANGLE CRITICAL?
The metal that the tungsten electrode is alloyed with can affect the way the electrode starts, how the tungsten handles temperatures, and the qualities of the final weld.
The choice of tungsten grind angle is also critical. The depth of penetration, width of the weld, and how much of the base material is affected by heat are all determined by the tungsten grind angle in GTAW welding. Knowing this Striking Precision Welding has chosen to acquire a tungsten grinder to apply a consistant angle with high quality surface finish and document angles within our weld procedures.
Aside from penetration, choosing a tungsten electrode grind angle is the amount of heat that a particular grind angle can endure before it begins to start spitting. When a tungsten electrode spits, particles of tungsten end up in the molten puddle, creating a tungsten inclusion in the weld. Tungsten inclusions should be avoided in any GTAW welding project, but in demanding fields like aerospace, nuclear power generation, and semiconductor manufacturing, in particular, they are unacceptable.
In GTAW, blunter electrodes are generally used in situations where a higher amperage is needed. This also limits the chances of the tungsten spitting and causing inclusions. Grinding a blunt tip can also cause hard arc starts as well as arc wander. Thin-walled materials, or other lower amperage jobs may benefit more from a sharper tungsten grind angle. One last technique is to grind a sharp taper but grind a slight blunt tip to help reduce the chances of tip breakage and inclusions in the weld.
Here is a great video of actual testing of angle grinds and effects on penetration.