History of Electron Beam Welding Process:-
1952 is viewed as the beginning of electron bar innovation. The physicist Dr. H.C. Karl-Heinz Steigerwald fabricated the main electron shaft handling machine. What must be difficultly worked out around then is underestimated today.
The historical backdrop of electron bar innovation started with the investigations by physicists Hittorf and Crookes. They first attempted to create cathode beams in quite a while (1869) and to dissolve metals (1879). These cathode beams were an intriguing actual wonder and lead to the disclosure of a specific sort of beam by Roentgen (1895), Thompson (1897), and Millikan (1905), which were portrayed as "quick electrons".
The warmth produced by the effect of the electrons was considered rather have a harmful impact at the hour of those examinations and endeavors were made to forestall this through cooling. The physicist Marcello von Pirani was quick to utilize this impact. He constructed a piece of contraption for softening tantalum powder and different metals utilizing electron radiates. In the accompanying time, an ever-increasing number of researchers explored different avenues regarding electron shaft innovation, which lead to the improvement of oscillographs, magnifying instruments, and the boring of metals. The primary obstruction as of now was the absence of adequately amazing vacuum siphons.
In 1948 another time in material handling started with the physicist Dr. H.C. Karl-Heinz Steigerwald. Around then, he was chipping away at the further improvement of electron pillar sources with higher forces for the development of electron magnifying lens.
Introduction:-
In this welding technique, a high jet of electrons moves at welding plates in which its kinetic energy converts into warm electricity. This heating strength is sufficient to meet the painting's portions and fuse them into one piece. This complete technique carried in a vacuum otherwise the electrons collide with air debris and loses their energy.
Working Principle of EBW:-
In general, the electron beam welding process is performed in a vacuum. In this process, the electrons are emitted from the heated filament called an electrode.
These electrons are speed up by applying high potential contrast (30 kV to 175 kV) among cathode and anode.
Higher the potential contrast, the higher the electrons' speed increase would be. The electrons get the speed in the scope of 50,000 to 200,000 km/s.
The electron beam is engaged through electromagnetic focal points. At the point when this high dynamic energy electron shaft strikes on the workpiece, high warmth is created on the work piece bringing about softening of the work material.
The liquid metal fills into the hole between parts to be joined and along these lines, it gets hardened and shapes the weld joint.
Equipment's of EBW:-
Power Supply: This process uses a power source to supply a continuous beam of electrons for the welding process. The voltage varies of fastening is regarding 5-30 kV for low voltage instrumentation or for skinny fastening and 70-150 kV for prime voltage instrumentation or for thick fastening.
Electron Gun: It is the heart of electron beam welding. It is a cathode tube (negative pole) that generates electrons and focuses them on a spot. This gun is mostly made of tungsten or tantalum alloys. The cathode filament heated up to 2500 degrees centigrade for continuous emission of electrons.
Anode: Anode is a positive pole that is just after the electron gun. Its main function is to attract a negative charge, (in this case electron) provide them a path, and don't allow them to diverge from its path.
Magnetic Lenses: A series of magnetic lenses allow only convergent electrons to pass. They absorb all low energy and divergent electrons and supply a high intense electromagnetic wave.
Electromagnetic lens and deflection coil: Electromagnetic lenses are used to focus electron blocks on workpieces and deflection coils bring the beams in the weld area needed. These are the last unit of the EBW process.
Work holding device: EBW uses a CNC table to hold the workpiece which can move in all three directions. The welding plates are clamped on a CNC table with the use of suitable fixtures.
Vacuum Chamber: As we probably are aware, entire this interaction happens in a vacuum chamber. Vacuum is created by the mechanical or electric-driven pump. The pressure ranges in a vacuum chamber are about 0.1 to 10 Pa.
Advantages of EBW:-
- High infiltration to width can be gotten, which is troublesome with other welding measures.
- High welding speed is obtained.
- High melting temperature material can be welded.
- due to welding in a vacuum superior weld quality obtained.
- High precision of the welding is obtained.
- Due to less heat-affected zone, distortion is less .
- Dissimilar materials can be welded.
- Low operating cost.
- The cleaning cost is negligible.
- Reactive materials like beryllium, titanium, etc. can be welded.
- High melting point materials like tungsten, columbium, etc. can be welded.
- Inaccessible joints can be made.
- A broad range of sheet thickness can be joined (0.025 mm to 100 mm)
Disadvantages of EBW:-
- Very high equipment cost.
- A high vacuum is required.
- High safety measures are required.
- Large jobs are difficult to weld.
- Skilled manpower is required.
Applications of EBW:-
- The EBM process is widely used to join materials that are refractive like columbium, ceramic, tungsten, etc. which are used in missiles.
- In space shuttle applications materials like zirconium, beryllium, titanium, etc. are used.
- In high precession welding for electronic segments, atomic fuel components, uncommon compound flies motor parts and pressing factor vessels for rocket plants.
- Dissimilar material will be welded like Invar with chrome steel.
 Process in detail along with History, Working Principle, Equipment's used, Advantages, Dis-advantages and Applications of EBW){kind=link}
0 Comments