The electrode recesses in water or air-cooled gas nozzles constrict the arc that causes the narrow, high temperature, high-velocity plasma jet to form.When the plasma jet hits the workpiece, recombination takes place, and the gas reverts to its normal state.This heat melts the metal, and gas flow ejects from the cut.Plasma gases are usually argon, hydrogen, or nitrogen.These inert gases replace air, but it requires a special electrode of hafnium or zirconium.It uses compressed air and makes this variant of the plasma process very competitive with the oy fuel process.Additionally, it cuts carbon manganese and stainless steel up to 20mm thick.Because they are easy to find and replace if and when needed.Plasma arcs can cut a very wide range of electrically conductive alloys, including plain carbon and stainless steel, aluminum and its alloys, nickel alloys, and titanium.