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What is plasma arc welding, its component and applications

Plasma arc welding (PAW) 

Today I will be discussing on what is plasma arc welding, its applications and components. Previously, some articles was published on arc welding process. Check out!

What is plasma arc welding (PAW)?

Plasma arc welding (PAW)

Plasma arc welding is another type of arc welding process that uses a non-consumable electrode just like tungsten inert gas welding (TIG), making them similar process. It creates its arc between the electrode and the workpiece. Plasma arc welding (PAW) coalescence is produced by heat obtained from a constricted arc setup between a tungsten electrode and the constricting nozzle, which is non-transferred arc. It can also be between a tungsten/alloy tungsten electrode and the workpiece, which is a transferred arc. This process has the ability to use two inert gases, one forms the arc plasma and the other create shields to the arc plasma. Same as TIG welding, filler metal may be or may not be added.

PAW welding is said to be an advance of TIG welding. in TIG welding, the open arc is shielded by argon and helium, but in plasma, special torch, using nozzle to separately pushed the arc and shielding gas to the torch. The arc is constricted pushed by a water-cooled small diameter nozzle by squeezing the arc, increasing its temperature, pressure, and intensely heat, helping to improve the arc stability.

Just as mentioned earlier, PAW arcs are form by two gas flow: luminal and turbulent flow. The luminal flows at low pressure and low flow of plasma gas, which is employed to ensure that the molten metal is not blow out of the weld zone. Whilst, the turbulent flows at high pressure and high plasma gas flows. These gases are argon, helium, hydrogen, or could be their mixture.

Components

The followings are the components of plasma arc welding.

  • Current and gas decay control: it is used to properly closed the key hole while terminating the weld in the structure
  • Fixture: it helps to avoid the atmospheric contamination of the molten metal under bend
  • High frequency generator and current limited resistors: this is used for arc ignition. Its starting system of the arc maybe separate or built into the system
  • Plasma torch
  • Power supply: it uses direct current power source either a generator or rectifier
  • Shielding gases: the two inert gases or mixtures of gases used
  • Voltage current: this is required in contour welding

Applications

Micro-plasma welding is traditionally used for welding thin sheets at minimum of 0.1mm thickness and wire and mesh section. It is used in the marine and aerospace industries. Plasma arc welding is used to weld pipes, and tubes of stainless steel and titanium. It is a good choice when repairing tools and die. This welding process is also used for welding and coating on a turbine blade. Finally, plasma arc welding is widely used in electronic industries.

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And that is it for this article, what is plasma arc welding. I hope you enjoy reading it. If so, comment and shared to help others. Thanks for reading!

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