Plasma Arc Welding (PAW) is a welding process that is similar to TIG welding. Like TIG welding, Plasma Arc Welding is precise and clean and both use Tungsten electrodes. The biggest difference between the two methods is that PAW allows the welder to position the electrode within the body of the torch, allowing the plasma arc to be separated from the shielding gas.
The plasma can then be fed through a nozzle, which constricts the arc and forces the plasma out at a much higher speed and temperature. The end result is faster welding with the same degree of precision and accuracy as TIG welding. Any metal that can be welded using TIG, can be welded using a plasma arc. The process is often used to produce high quality joints in the chemical, petroleum, and aircraft industries.
The Concept Behind Plasma Arc Welding
Like other forms of welding, the electric arc is created between the electrode and the metal with PAW. Unlike other methods, PAW relies on two inert gases; one forms the arc plasma and the other shields the arc. Another unique feature of plasma arc welding is that the weld is produced by a combination of the heat obtained from the constricted arc between the tungsten electrode and the constricting nozzle or between the tungsten electrode and the job. Temperatures can be 28,000 °C (50,000 °F) or higher in Plasma Arc Welding.
Because the torch can be adjusted to vary the current, gas flow, and the nozzle size, PAW can be used on many different materials and processes, from very narrow penetrations to very heavy and deep welds. One interesting feature about plasma arc torches is that they can be used either to weld or cut metals simply by adjusting the torch settings.
Advantages And Limitations Of Plasma Arc Welding
Plasma arc welding has only been around since 1954 but it has grown and changed quite a bit since that time. It is now being used on a wider variety of metals than ever before and more uses are discovered all the time.
Aside from being precise, clean, and versatile, PAW advantages include: longer arc lengths and greater tolerances to change in arc lengths and the ability to create deep and high quality welds.
As a more complex form of welding, there are more challenges to this method than other methods. Sometimes 3 gases are required – the arc plasma gas, the shielding gas, and sometimes a third gas is used as a back-purge and trailing gas. But the third gas is only needed for certain materials, not every project.
PAW also requires more specialized equipment than TIG welding and requires the welder to have a strong knowledge of the equipment and the gases.
Learn More About Plasma Arc Welding At Josef Gas
If you are ready to learn more about Plasma Arc Welding, contact Josef Gas online or in person at 201 Basaltic Road in Concord, Ontario. Visit our soon to be newly renovated showroom to see the latest equipment and gear or to speak with one of our team members about PAW.