What is Electron Beam Welding?
Definition: Electron beam welding is a fusion welding process in which the metals are joined due to heat produced by the collision of high-velocity electron beam with the metal.
The electron beam welding operation is performed under the vacuum chamber so that the dissipation of electron beam can be prevented.
How does electron beam welding work?
The complete setup for the electron beam welding is shown in the line diagram above.
The components used for electron beam welding are listed below.
- Electron gun
- Electromagnetic focusing lens
- Working chamber or Vacuum chamber
- Workpiece carriage
- Power supply and other electronics
On supplying a high voltage electric current, the electron beam is emitted from the electron gun.
These electrons have a very high speed and hence the electron beam possesses very high kinetic energy.
In order to focus the electron beam, the electromagnetic focusing lens are used (see above diagram).
Further, the focused electron beam is allowed to fall on the workpiece surface which is to be welded.
When this electron beam containing high kinetic energy strikes with the workpiece surface, the kinetic energy is converted into heat energy.
This heat energy is so high that it can melt the metal surface.
Due to this melting of the surface, the welding of the metal pieces takes place.
The electron beam is very narrow and it can create a high quality weld with a deep penetration.
Using electron beam welding, the holes (or penetration) having depth to width ratio of 20:1 can be achieved.
What exactly happens when the electron beam strikes the workpiece surface?
As the high-velocity electron beam strikes the workpiece surface, its kinetic energy gets converted into heat.
This heat can vaporise the metal and creates the keyhole.
By using Electron beam welding (EBW), thin keyholes can be produced which have a narrow heat affected zone (HAZ).
Why is vacuum chamber used in electron beam welding?
There are two main reasons for using a vacuum chamber in EBW.
- The vacuum chamber prevents the weld pool from contamination of atmospheric gases.
- Also the electron beam remains more stable in vacuum conditions.
Electron beam welding uses/applications
Uses/Applications of electron beam welding are mentioned below.
- Electron beam welding is used to weld many similar metals and alloys like;
- Stainless steel
- Super alloys
- Refractive metals, etc.
- Various dissimilar metals can also be welded using electron beam welding, for example;
- Carbon steel to bronze
- Aluminum to silver
- Copper to inconel, etc.
How electron beam welding differs from laser welding?
Here is a difference between electron beam welding and laser welding.
|Electron beam welding||Laser welding|
|1). In electron beam welding, the electrons are focused on the workpiece.||1). In laser welding, the photons are focused on the workpiece.|
|2). The tendency of electron beam to diverge during the contact with the workpiece surface is very less. So it gives deeper holes with less distortion.||2). The laser beam have more tendency to diverge when it comes in contact with the workpiece surface.|
|3). Vacuum chamber is used in electron beam welding process to prevent the atmospheric contaminations.||3). In laser welding process, the inert gas is used as a shielding gas.|