Tungsten Electrode–Balled, Pointed or Truncated Shape

As we know, different type and shape of tungsten electrode you used will influence the arc quality and welding performance that you will achieve. This article will brief introduce the performance and usage tip of different tungsten electrode shape. 

A balled tip is generally used on a pure tungsten electrode. Besides, it is suggested for use with the AC process on sine wave and conventional squarewave TIG welders. What’s more the diameter of the balled end should not exceed 1.5 times the diameter of the tungsten electrode. Because a larger sphere at the tip of the electrode can reduce arc stability and/or fall off and contaminate the weld.

A pointed or truncated tip is generally used on pure tungsten electrode, ceriated tungsten electrode, lanthanated tungsten electrode and thoriated electrode. And a pointed or truncated tip of electrode should be used for inverter AC and DC welding processes. To process electrode tip to a pointed or truncated shape should use a grinding wheel specially designated for tungsten grinding which can avoid contamination and one that is made of borazon or diamond which can resist tungsten’s hardness. Note: if you are grinding thoriated tungsten, make sure you control and collect the dust, have an adequate ventilation system at the grinding station and that you follow manufacture’s warnings, instructions and MSDS sheets. What’s more, during grinding should put the tungsten electrode straight on the wheel versus at a 90-degree angle to ensure that the grind marks run the length of the electrode. So it will reduce the presence of ridges on the electrode that could create arc wandering or melt into the weld puddle, causing contamination.

Generally, when welding with lower currents on thinner materials, it is best to use the pointed tungsten electrode. Because A pointed tungsten allows the welding current to transfer in a focused arc and helps prevent thinner metals, such as aluminum, from becoming distorted. However, using pointed tungsten for higher current applications is not recommended. Because, at the higher current it can blow off the tip of the electrode and cause weld puddle contamination. So at the higher current, truncated tip will more suitable than pointed shape.

In any application, different type and shape of tungsten electrode has distinct advantages and disadvantages. That’s why, regardless of type of material you are TIG welding or whether you are using an AC or DC process, it is always important to choose tungsten electrode shape and type. Doing so can maximize your TIG welding success and is one of the best defenses against contamination and rework.