Ranges of Application for Plasma Welding

Plasma welded floater container
Floater container made of stainless steel (wall thickness 0,3 mm)
Plasma welded knife handle
Knife handle(plasma welded with additional wire)
Plasma welded pressure container
Pressure container (wall thickness 2,4 mm)
Micro plasma welded valve stem
Valve stem (welded gas-tight )

Plasma welding is suitable for welding all fusion-weldable metals. The characteristic of comparably high seam shape factor (ratio seam depth/seam width) and the hereof resulting low distortion and high weld seam quality have led to use this procedure mostly for high-alloyed steels. The high viscosity of weld pools of these steels makes it possible to work at butt joints without pool protection. The seam root develops freely, without "falling through" of molten pool.

Also when welding heat-conductable metals like copper and copper the high capacity density leads to advantages.

Lately plasma welding of aluminium with the electrode at the positive pole is being applied more and more.

Plasma welding of non-alloyed and low-alloyed steels is being used more frequently. The high seam shape factor, as can be obtained with plug welding, can lead to increased development of pores due to insufficient gas release of workpiece. Therefore - under certain circumstances - the use of additives is required. The higher productivity compared to TIG-short time welding account for the use of procedure. 

When welding thin sheets up to 3 mm (4mm) manual welding has its right besides the mechanical welding. However, with increasing sheet thickness and current manual welding is being discarded.

When "plug welding" the strong plasma arc penetrates the material - building a  welding eye and the plasma beam is also visible at the bottom side of the sheet. Behind the plasma beam the welding material flows together again and builds the plasma weld seam. The process of plug welding is applied for square butt welding of sheet thicknesses for approx. 3 mm to 8 mm.

When processing very thin foils  the process of mechanical welding should be favoured. The micro plasma welding (0,1 to 25 A), however, facilitates also  manual welding with low weld current. When TIg-welding with currents of < 10 A the arc has to be kept that short, so that welding will cause difficulties. The different arc characteristic of plasma arc allows a considerably longer arc.

The "hardness" of plasma arc can be influenced by the choise of plasma nozzle and quantity of plasma gas. A large nozzle diameter combined with low amount of plasma gas leads to a soft plasma arc. The hard plasma arc, being applied for welding thicker sheets with  Informationen über das Plasmastichlochschweißen"plug weld technology occurs by choosing a smaller-sized nozzle and a higher amount of plasma gas.