Plasma Arc Welding Methods:

The transferred arc might be used for welding as well as cutting and is utilized with two different techniques :

• At low currents for welding sheet metal less than 1.5 mm thick.
• At currents up to 400 A for welding thick metal utilizing the deep penetrating keyhole technique.

While using the plasma arc for welding, additional inert gas shielding is needed which is provided by an annular flow concentric along the primary gas pass through the plasma arc chamber. Generally A d.c. electrode-negative arc is utilized except for aluminium where the polarity is reversed. Arc voltages are higher than tungsten-arc welding and might go up to 50. The orifice through that the plasma flow is approximate 2.5-mm diameter.