electron beam welding

Electron Beam Welding Overview

Electron Beam Welding is a fusion welding process. It uses the kinetic energy of highly accelerated electrons emitted by the cathode tube or electron gun. When the highly accelerated electrons are bombarded on the workpiece, their kinetic energy is converted into thermal energy. The process is performed in vacuum conditions for preventing electron beam dissipation. Karl-Heinz Steigerwald, a German physicist, invented the welding process in 1949. In modern times, many high sophisticated industries use this process in their projects. So, in this article, read various aspects of electron beam welding (EBW).


Post Highlights:

  • Electron Beam Welding Means
  • EB Welding Principle
  • Features of EBW
  • Equipment Used
  • EBW Applications
  • Advantages
  • Disadvantages
  • Work Opportunities
  • Salary Trends

What is Electron Beam Welding?

Electron Beam welding is a fusion welding process. During the process, the kinetic energy of highly accelerated electrons (due to the influence of anode) is converted into thermal energy. As a result, this thermal energy melts the metal pieces and molten parts of the metal are joined together. Further, it forms a joint and the joint cools down to form a weld.

Electron Beam Welding Principle

The working procedure of electron beam welding is as follows-

After the high voltage current is applied across the cathode tube, the filament present in it heats up and starts producing electrons. The heat is required to maintain at approximately 2500°C for the constant flow of electrons. These emitted electrons have very little energy. Then, the anode, a positively charged electrode, created a potential difference between the two terminals. Due to this potential difference, the electrons are accelerated towards the anode.

Further, the highly accelerated electrons pass the anode and enter into the region having less electric field. Next, it leads to the deflection of some electrons from their path. To focus at one place, the focusing coil is used. The coil focuses the electrons and provides them a focusing trajectory (path).

Then the deflecting coil is used to deflect the electrons on the welding area for higher penetration power. When the highly accelerated electrons strike the surface of metal or workpiece placed on a CNC (Computer Numeric Controller) slab, the kinetic energy of these electrons gets converted into thermal energy. Consequently, it heats up the metal to a molten state. Then by using a CNC machine, a welder adjusts the workpiece for welding. And it cools down to form a weld.

Features of Electron Beam Welding

  • The whole process takes place in the vacuum chamber, to forbid the electron to collide with the air particles and gasses.
  • It can melt up to 100mm (10cm) or more thick metal plates.
  • The energy transfer occurs by the conduction of heat across the
  • surface of the workpiece.
  • Computer numeric controller slab is used because it is very hard to handle molten metal.
  • From lesser thick to more thick slabs the accelerating voltage varies from 30kV to 200kV.
  • It can weld simple longitudinal weld seams and complicated three-dimensional as well.
  • For the constant flow of electrons, the temperature of filament present in the electron gun should be maintained at 2500°C.

Electron Beam Welding Equipment

Electron beam welding uses the following basic equipment-

1. Anode
The anode is a positively charged electrode and used to create the region of an electric field. As it is positively charged, it attracts the electrons towards itself. Then, it leads to the acceleration of the electron.

2. Electron Gun
An electron gun or cathode tube ejects the electrons when the temperature of filament presented in it reaches approximately 2500°C. It is mainly made up of tungsten or tantalum alloy.

3. Power Supply
Electron beam welding requires a high voltage power supply. A controller is connected to the power supply so as to control the voltage of current supplied to the electron gun or cathode.

4. Focusing Coil
Right after the anode, a focusing coil or convergence coil is present. It mainly acts to focus the electrons on a single path.

5. Deflecting Coil
The coil is mainly employed to deflect the focused electron beam on the workpiece.

6. Vacuum Chamber
A vacuum chamber is a very important part of the whole process and used to forbid the collision of electrons with the air particles.

7. CNC Slab
As the whole process takes place in the vacuum, the workpiece is placed on the Computer Numeric Controller slab. Further, the CNC slab eases the mobility of the workpiece as per requirement.

Electron Beam Welding Machines

Normally, the following machines are used-

  • Non-Vacuum Electron Beam Welding Machines
  • Reduced Pressure Electron Beam Welding Machines
  • Special High-Pressure Welding Machines
  • Universal High-Pressure Welding Machines

Electron Beam Welding Applications

Being one of the best processes, it has a large number of applications. The welding type is employed in the following areas.

  1. The defense industry uses EB welding for manufacturing military equipment due to the requirement of highly accurate products which can survive under extreme conditions.
  2. Electron beam welding can weld a wide range of slabs from very less thickness approximately 0.01mm to a high thickness of about 10mm.
  3. Using this process, the oil and gas storages are made for higher accuracy because a very small leak may cause a lot of problems.
  4. The aerospace industry mostly depends on electron beam welding. The EB welding-made products are used in rockets’ engines, and spacecrafts’, etc.
  5. EB Welding cuts down the cost of production and can be used to weld small components. That is why transmission assemblies can be easily made by this process.

Electron Beam Welding Advantages

The benefits of the process are as follows-

  1. As the whole process takes place in a vacuum, there are very few chances of oxidation.
  2. A filler rod is not required for welding as metal itself melts and joins together.
  3. It can weld both very thin and thick metal plates.
  4. The process does not require a shielding gas for laying welds.
  5. It produces well-furnished and consistent welds.
  6. There are very few chances of Distortion.
  7. Electron beam welding can weld successfully alloy steels, nonferrous metals, structural steels, and even gas-sensitive special metals.
  8. It is a precise technique, highly repeatable, offers precise weld penetration, and creates strong and pure joins.

Electron Beam Welding Disadvantages

All welding types have their own minor or major drawbacks despite being used in the welding industry.

  1. It is a very costly process and requires frequent maintenance.
  2. The process requires both theoretical knowledge of the whole model and its components.
  3. Electron Beam Welding is a complex process as the whole setup is required for it to work.
  4. The process needs a highly trained operator because a little mistake can affect the welding process.
  5. EB welding cannot weld metal with high vapor pressure.

Electron Beam Welder Career Scopes

Electron beam welders are highly demanded in the welding industry due to EB type being an accurate technique of welding. They can work in companies that make rockets, aircraft, automobiles, and military equipment, etc.

Electron Beam Welder Salary

The salary of every employee is different in the welding industry as per their profile and work. Many factors affect the salary trends. Due to its use in different industries, the demand for electron beam welders increased. Normally, an EB welder earns from $28.57 to $42.85/hour. The figure may vary depending on local circumstances, demands, competitions, vacancies, and availability of applicants for the jobs.

Conclusion

Electron Beam Welding is one of the highly applicable and accurate processes despite having some drawbacks. Due to its high cost, it cannot be used by small welders. So, they have to use other techniques like FCA welding, and AH welding, etc. Further, the welding process has created a revolution in the area of materials processing. Learning is a life-long process. And this welding type is a new challenge to hands-on. Thus, aspiring people can use the above information for their respective purposes such as study, job, project, etc.

Related: Other Welding Types

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