What is Plasma Arc Welding (PAW) Process : Introduction, Working Principle, Types of Equipment's, Application, Advantages, Dis-advantages

 Introduction :

This is a fusion welding process where the combination is removed by heating up the work with a limited arc set between tungsten electrodes and workpieces that cannot be consumed or between electrodes that cannot be consumed and the nozzle is limited.

The shielding of the welding pool is obtained by the hot ionized gas produced by passing an inert gas through the arc and the tightened nozzle.

The filler material might be applied.

Working Principle :

In the PAW process, the room is cleaned and the edges are prepared. An arc is established between a non-consumable tungsten electrode and a workpiece or between a non-consumable electrode and a tightened nozzle.

An inert gas passes through the internal orifice surrounding the tungsten electrode then, thereafter, the gas is ionized and carries out electricity.

This state of ionized gas is called plasma. The plasma arc is allowed to pass through the tightened nozzle, causing high energy density and current.

Subsequently, high concentrated heat and very high temperatures are reached.

At a higher flow rate (10-301 / min), the inert gas is necessary to pass through the external gas nozzle surrounding the internal gas nozzle to protect the welding pool.

Types of equipment of PAW :

• Power Source: The PAW cycle required a powerful DC supply to produce an electric sparkle in the middle of the tungsten anode and welding plates (For moved PAW Process) or in the middle of the tungsten terminal and release spout (For Non-moved PAW measure). One of the primary highlights of plasma circular segment welding which makes it not quite the same as TIG is its low ampere welding capacity. This welding can weld at a low ampere of around 2 amp and the most extreme current which it can deal with is around 300 amp. It needs around 80 volts for legitimate working. The power source consists transformer, rectifier, and control console.

• Plasma arc torch: This is the main piece of the PAW cycle. This torch is quite similar to used in TIG welding but too complex. It comprises four fundamental parts which are tungsten anode, collets, inward nozzle, and external nozzle. The tungsten electrode is held by the tailstock. The collet is available in varying diameters. The internal gas spout supplies idle gases inside the light to frame plasma. The outside nozzle supplies shielding gases which 'protect the weld area from oxidation. These nozzles wear out rapidly. PAW lights are water-cooled on the grounds that a circular segment is contained inside the light which creates high warmth, so a water coat is given external light.

• Shielding and Plasma Gas Supply: By and large, plasma gas is equivalent to protecting gas which is provided by a similar source. Mainly inert gases like argon, Helium, etc. are utilized as both idle and protecting gases. This gas is provided at both dormant and external spouts.

• Filler Material: Generally no filler material is utilized in this welding interaction. On the off chance that the filler material is utilized, it is straightforwardly taken care of into the weld zone.

Application of PAW :

• Piping and tubing of stainless and titanium.
• A submarine, aeronautical industry, and jet engine manufacturing
• Electronic components.

Advantages of PAW :

• Welding speed is higher.
• Penetration is more.
• Higher arc stability.
• The distance between light and workpiece doesn't influence heat fixation on the work dependent to some degree. 
• The expansion of filler material is simpler than that of the TIG welding measure.
• A thicker job can be welded.
• A higher profundity to width proportion is acquired bringing about less mutilation.

Disadvantages of PAW :

• Higher radiations.
• Noise during welding.
• The process is complicated and requires skilled manpower.
• Gas consumption is high.
• Higher equipment and running cost
• Higher open circuit voltage requiring higher security measures to take.