The history of welding can be traced back to the Bronze and Iron Ages. Without this joining process, it wouldn’t have been possible to manufacture many of the components that create machines and structures that we rely upon.
Welding uses high heat to melt the parts being joined together. Fusion is caused once those parts are allowed to cool down. It’s a fundamentally different technique compared to brazing or soldering in which the base metal isn’t melted.
Aside from melting the base metal, the process also requires a filler material. This is added to the joint so that a pool of molten material can be formed. When it cools down and depending on the weld configuration, this joint can end up being stronger than the base material.
For the longest time, forge welding was the only welding process. It was used by blacksmiths for millennia to join iron and steel. They did that by heating and hammering the metals until they joined together. Arc welding and oxy-fuel welding were the first processes to develop late in the 19th century.
A variety of different energy sources can be used for welding metals. Gas flame and an electric arc are among the most commonly used sources. Others include ultrasound, friction, and electron beam. Welding can be performed in different settings, including but not limited to open air, underwater, and even outer space.
There is now a push to achieve energy efficiency and sustainability in welding. Electron beam welding has shown the most promise as the method having the lowest environmental impact.
What is electron beam welding used for?
Electron beam welding is used to weld thick material into the thin material. It also makes it possible to join dissimilar metals, these include metals that have different melting points and thermal conductivities. This means that some combinations that can’t be welded by other methods can easily be electron beam welded.
High power electron beam welding systems are used in a wide range of industries. They include defense, automotive, aerospace, semiconductor, power generation, and more. Many aircrafts today have components that were manufactured with electron beam welding. The same holds for most automobiles.
How does electron beam welding work?
Electron beam welding works by heating a tungsten filament and applying power until the filament starts to give off electrons. These free electrons are sped up and focused using electrical fields and magnetic lenses.
These electrons thus attain massive amounts of kinetic energy. Once they strike a metal part, that kinetic energy is transferred into the molecular lattice of the metal which causes the metal to heat up almost instantly. The power delivered by an electron beam can be as high as 10,000 kW/mm3. There’s enough power in an electron beam welding system to vaporize metal.
There is an important prerequisite, though. Electron beam welding can only take place in a vacuum. The electrons would simply be scattered and diffused by air and gas particles if the process is carried outside a vacuum chamber.
This thus adds a limitation to the scope of the work, in that the size of the part that needs to be welded has to be smaller than the size of the vacuum chamber.
Filler materials aren’t typically used or required with electron beam welding. It only requires a precise fit between the parts to be joined together. These parts are securely tied down to a motion-controlled table so that the areas that need to be in contact with the beam can be moved precisely.
How much does an electron beam welder cost?
Electron beam welding machines can typically be split into two categories. There are low voltage machines rated at 60 kV and high voltage machines at 150kV. A conventional high voltage machine can produce a weld in steel 2 inches deep with a width that’s almost 10% of the penetration depth.
Prices for electron beam welding machines can be a bit on the higher side. The vacuum chamber also makes up a major cost component for these machines. The cost can range from tens of thousands of dollars to millions.
Electron beam vs. laser beam welding
Electron beam welding utilizes a high-speed stream of electrons while laser beam welding relies on a focused beam of photons directed at the surface of the part that needs to be welded. The laser acts as a concentrated heat source to help join the materials together.
The two main methods of laser beam welding are continuous wave and pulsed output. The former blasts a continuous laser beam over the part during the weld. The pulsed output throws a small pause between the laser blasts. It’s a better option for welding heat-sensitive metals.
Laser beam welding is a lower-cost alternative to electron beam since it doesn’t require any vacuum chamber. The tooling requirements are simple, the cycle times short and a minimal heat-affected zone can be achieved.
Is electron beam welding done with renewable energy?
Electron beam welding can be done with renewable energy. The low or high voltage power source used to power the machine can be hooked up to a renewable source of energy.
There exist renewable energy systems such as solar and wind generation plants that can meet the power requirements of even the largest electron beam welding machines.
Can it be used sustainably?
Electron beam welding can be used sustainably. It’s one of the most energy-efficient, eco-friendly, and sustainable welding methods. Since the process is carried out in a vacuum, there’s no risk of a reaction between the material and the air.
The efficiency of the energy conversion process from the power source to the beam output power is much higher and more efficient compared to other methods like laser welding. Electron beam welding complies with strict EU regulations on resource efficiency and sustainability.
The future of electron beam welding?
There has been a significant advancement in electron beam welding technology over the past few decades. The compound annual growth rate for this market is estimated to be around 3.2% from 2019 to 2024. This goes to show that steady growth is expected in the future. Major industries are now rapidly turning towards the use of electron beam welding.
The automobile industry is expected to become the biggest adopter of this method due to its durability, flexibility, and efficiency.