Applications:

The most broadly used plasma-arc is the micro-plasma variation. Compared with low-current tungsten-arc welding the micro-plasma procedure has a number of important advantages, for instance when used below 5 A this is the more stable heat source and exhibits a stiffer more directional arc column. Particularly while an edge weld is being made this permit the arc to be directed more positively with fewer tendencies to wander. Higher tolerance to variations in torch work distance is also exhibited and the risk of tungsten inclusions obviated.

Micro-plasma is specifically suitable for edge welds in sheet of less than 0.5 mm and for welding wire-mesh components such like filters. For stainless, mild steel,  and heat-resisting alloys an argon-hydrogen mixture is utilized for shielding the plasma arc. With low-alloy steels, copper alloys and aluminium, hydrogen ought to not be used because it causes cracking in alloy steels or porosity in and copper and aluminium. Helium or Argon is used instead.

Pulsed operation is feasible and provide the same additional advantages that pulsed current ilustrated over continuous current for inert-gas tungsten arc welding.