The document discusses electron beam welding (EBW), a fusion welding process that uses a beam of high-velocity electrons to melt materials being joined. It describes how EBW machines work by accelerating electrons via high voltage to concentrate their kinetic energy on a target. The document classifies EBW machines, explains their components and principles, and discusses process parameters, applications, advantages, and fields of EBW use, noting it can join a variety of materials with high precision and fewer defects compared to arc welding.

1. ELECTRON BEAM
WELDING
MODERN MANUFACTURING SYSTEM
D.PALANI KUMAR,
Assistant Prof. / Mech. Engg.,
Kamaraj College of Engg. & Tech.
Virudhunagar.

2. INTRODUCTION
 Electron beam welding process is used in a variety of
industries.
 Applications range from fully automated, high productivity
and low cost automotive inline part production to single
part batch processes in the high cost aircraft engine
industry.
 The EB welding process is well positioned to provide
industries with highest quality welds and machine designs
that have proven to be adaptable to specific welding tasks.

3. CLASSIFICATION OF EBW
MACHINES
 By accelerating voltage:
1. high voltage machine (U =150 kV)
2. Low voltage machine (U =60 kV)
 By pressure:
1. high vacuum machine
2. fine vacuum machine
3. atmospheric machine (NV-EB welding)
 By machine concept:
 conveyor machine
 clock system
 all-purpose EBW machine
 local vacuum machine
 mobile vacuum machine
 micro and fine welding machine

4. PRINCIPLE
 Electron beam welding(EBW)is a fusion welding process
in which a beam of high velocity electrons is applied to the
materials being joined.
 Principle : Electrons are accelerated by a high difference
electrical potential and concentrated on a target.
 The electron’s kinetic energy is then transformed, for the
most part, into thermal energy melting the metal and
producing welds.

5. SCHEMATIC DIAGRAM

6. MAJOR COMPONENTS
 The electron beam welding machine is made up of three
main components
1. beam generation,
2. beam manipulation and
3. forming and working chamber.
 These components may also have separate vacuum
systems

7. ELECTRON BEAM CREATION
 In the inter-electrode space, the electrodes geometry
defines the electron trajectories.
 First, the electron beam converges in the anode. Then, the
beam continues by inertia and diverges.
 In order to be used for welding, the beam is focused by an
exciting coil placed in the gun.
 The focus length is set up by current adjustment inside the
focusing coil.

8. WORKING
 Current is given to cathode in vacuum chamber and heated
up to 2000 °C.
 Electron beam gun operates at:
High voltage (e.g., 10 to 150 kV typical) to accelerate
electrons
Beam currents are low (measured in milliamps)
 A modulating electrode, the so called “Wehnelt cylinder”,
which is positioned between anode and cathode, regulates
the electron flow.
 The electron beam which diverges after having passed the
pierced anode, however, obtains the power density which is
necessary for welding only after having passed the adjacent
alignment and focussing system.

9. WORKING CONT……..
 A deflection coil assists in maintaining the electron beam
oscillating motion.
 An additional stigmator coil may help to correct aberrations
of the lenses.
 The energy conversion in the work piece, which is
schematically shown in Figure ,
 It indicates that the kinetic energy of the highly accelerated
electrons is, at the operational point, not only converted
into the heat necessary for welding, but is also released by
heat radiation and heat dissipation.

10. WORKING CONT……..
Energy dissipation of electron beam

11. WORKING CONT……..
 The impact of the electrons, which are tightly focussed into
a corpuscular beam, onto the work piece surface stops the
electrons.
 Their penetration depth into the work piece is very low, just
a few μm.
 Most of the kinetic energy is released in the form of heat.
 The high energy density at the impact point causes the metal
to evaporate thus allowing the following electrons a deeper
penetration.
 This finally leads to a metal vapour cavity which is
surrounded by a shell of fluid metal, covering the entire
weld depth, as shown in below Figure

12. WORKING CONT……..
Principle of deep penetration welding

13. WORKING CONT……..
 This deep-weld effect allows nowadays penetration depths
into steel materials of up to 300 mm, when modern high
vacuum-high voltage machines are used.
 The diameter of the cavity corresponds approximately with
the beam diameter.

14. VACUUM ENVIRONMENT
NECESSITY
 Due to collision of free electrons and gas molecule:
-Induce beam dispersion
-decrease in the carried power density.
Therefore the gun and the piece to be welded are vacuum
pumped.
Three Vacuum Levels in EBW
1. High-vacuum welding – welding in same vacuum chamber
as beam generation to produce highest quality weld
2. Medium-vacuum welding – welding in separate chamber but
partial vacuum reduces pump-down time
3. Non-vacuum welding – welding done at or near atmospheric
pressure,

15. PROCESS PARAMETERS
 The parameters related to the electron beam:
1. accelerating voltage, Ua
2. beam current, If
3. focusing current, F
4. beam diameter, d
 The parameters characteristic to the welding features
1. The type of the material,
2. thermo-physical & chemical features of the material
3. Work piece thickness

17. PROCESS PARAMETERS CONT…
 Other parameters: welding speed v, focal distance dt,
(the distance from the inner surface of the gun to welded
work piece), vacuum pressure in the electronic gun
chamber cannon Pt, vacuum pressure of the welding
chamber Ps, preheating temperature Tpr, heat treatment
Electron beam welding main parameters

18. PROCESS PARAMETERS CONT…
 The variation law of input factors in the process
(recurrence relations) can be written as a matrix (proposed
by Vigier) but also by using the method of least squares it
can be written in the form of relations 1-7.
 The penetration depth is an important factor critical to the
quality of an electron beam weld

19. PROCESS PARAMETERS CONT…
 If the focalization current (F) is maintained at a
constant value (744 mA) the regression function
has the main expression

20. PROCESS PARAMETERS CONT…
 The empirical functions determined emphasize the increase
in the depth of penetration and weld width along with an
increase in intensity value of the If current electron beam
 With increasing intensity of the beam current, there is a
greater transfer of energy and the area affected by the
melting is greater.
 Increasing the speed of welding means that the maintaining
time of work piece under the electron beam action is lower
and, as such, the penetration depth and width of welding
bath will have a lower value.

21. WELDING SPEED VS. DEPTH OF
PENETRATION

22. WELDING SPEED VS. DEPTH OF
PENETRATION

23. COMPARISON OF EBW WITH
CONVENTIONAL WELDING
 Compared with arc welding processes, EBW improves
joint strength 15 percent to 25 percent.
 It has a narrow heat-affected zone (HAZ), which results
in lighter-weight products.
 Geometric shapes and dimensions are highly stable,
particularly when it is used as a finish operation.

24. ADVANTAGES OF EBW
1. Thin and thick plate welding (0,1 mm bis 300 mm)
2. extremely narrow seams (t:b = 50:1)
3. low overall heat input => low distortion => welding of
completely processed components
4. high welding speed possible
5. No flux or shielding gas required
6. high process and plant efficiency

25. DISADVANTAGES OF EBW
1. electrical conductivity of materials is required
2. high precision of seam preparation
3. beam may be deflected by magnetism
4. Safety concern: EBW generates x rays‑
5. Rapid solidification rates can cause
cracking in some materials

26. APPLICATION
 Precision Aerospace Gears Weld
 Joint Geometry : radial circumferential weld
 Rotate at high speeds and operate at high loads,
require virtually defect free welds.

27.  Turbocharger Impeller Weld

28.  Turbine Blade Repair Weld
 Joint Geometry: butt weld
In a typical fan blade repair, the damaged
leading edge section is removed and a "patch" is
electron beam welded in place.

29. EBW FIELDS OF APPLICATION
 Industrial areas:
1. automotive industries
2. aircraft and space
industries
3. mechanical engineering
4. tool construction
5. nuclear power industries
6. power plants
7. fine mechanics and
electrical
8. industries
9. job shop
 Material:
1. almost all steels
2. aluminium and its alloys
3. magnesium alloys
4. copper and its alloys
5. titanium
6. tungsten
7. gold
8. material combinations
9. (e.g. Cu-steel, bronze-
steel)
10.ceramics (electrically
conductive)

30. REFERENCE
1. Dr.G.Schubert. Electron beam welding process-
process applications and equipment.PTR
precision technologies inc.

31. Thank you