Metallurgy and Materials Engineering Department, University of Punjab Lahore

1. ELECTRON BEAM WELDING
Group 04
Muhammad Ans (M14-349)
Muhammad Zeeshan (M14-336)
Muhammad Ilyas (M14-321)
Ali Hassan (M14-338)

3. ELECTRON BEAM WELDING (EBW)

4. INTRODUCTION
Definition:
It is fusion welding process in
which a beam of high velocity
electrons applied to two materials
or work pieces to be melt and
joined.
As high velocity electrons strike
the surface to be joined, their
kinetic energy changes to thermal
energy causing work piece to fuse.

5. PRINCIPLE OF OPERATION
 The electron beam is produced in high vacuum environment by electron gun.
 The stream of electrons is given off from a tungsten filament which is heated
to about 2200’C.
 The electrons gathered and shaped into beam by potential difference.
 The beam is focused by passing through the field of electromagnetic or
magnetic coil.
 Beams is focused to about 0.25 to 1mm diameter and power density of
about 10kw/mm2.
 The operation is carried out in a vacuum in which the distance is only 1mm
from the work piece.
 Deep penetration and very narrow affected zone is achieved by Electron
beam welding.

7. PROCESS
 The cathode of electron beam gun is negatively
charged filament.
 When heated it emits electrons.
 These electrons accelerated by electric field.
 As pass through the hole they focused by an
electromagnetic coil to a point at surface of work
piece.
 The current range is 50-1000mA and 30-175kV.
 The electron beam of very high intensity melt the
metal.
 The diameter of focused beam is 0.3 to 0.8mm.
 More density causes deep penetration (key
hole).
 The energy required in per unit length for beam
is 1.5kJ/cm.
 Speed should be maintained otherwise gas
bubbles will not leave.

8. MATERIALS TO BE WELDED BY
EBW
Almost all steels.
Aluminum and its alloys.
Magnesium alloys.
Copper and its alloys.
Titanium.
Tungsten.
Gold.
Material combination (e.g. Cu-steel, bronze-steel).

9. • Electron beam gun
• Vacuum chamber
• Vacuum pumping
• Telescope
• Work piece
• Power unit
Necessary Equipment

10. • The gun consist on a filament , cathode, anode and focusing coil.
• The cathode is generally made of tungsten and heated to a
temperature of 2500°C.
• Basic function of electron beam gun is to generate free electron
at cathode.
• Accelerate these electron to sufficient high velocity.
• To focus them over a small size of spot .
Electron Beam Gun

13.  All those Products, which require relatively low
distortion, are amenable to electron beam
welding technology.
 Medical: Many medical devices are preferably
welded with an electron beam because of the
precise nature of the process and the
autogenous welding.
 Electronic: Electron beam welding process lies
in its robustness to join materials like aluminum,
copper or stainless steels, which are commonly
used in semiconductor fabricating equipment
and electronic packaging.
Applications

14.  Oil & Gas Equipment:
The flexibility of the Electron Beam
Welding process can produce custom
tailored joints with small heat affected
zones and minimal heat affects to the
parent material.
 Automotive:
The electron beam is used to weld a
multitude of gear/synchronizer,
clutch/shaft and planet carrier
components for manual and automatic
transmissions as well as torque
converters and impellers/shaft
assemblies for turbochargers.
Continue….

15. The Electron Beam Welding process is used for
demanding joining tasks in many low- and high-
tech applications within some of the most
sophisticated defense systems.
 Power generation:
High value components, critical to the
functionality of complex power generating
systems, are preferably welded with an electron
beam.
 Aerospace:
The aerospace industry heavily depends
upon electron beam welding as a key
manufacturing technology. EB Welded
components are used in aircraft & rocket
engines, sensors, gears, actuators and air
frames.
CONTINUE..

16.  Dissimilar Metals: also allows joining of dissimilar metals, i.e. those with
different melting points and thermal conductivities. Some combinations
which are un-weldable by other conventional processes are thus readily
electron beam welded.
 Deep narrow welds: High depth-to-width ratio eliminates multiple-pass
welds. Penetration from .001” to 2”.
 Strength: Welds up to 95% of the strength of the base material.
 Versatility: Precise control and repeatability at speeds from 1 to 200 inches
per minute.
 High Purity: Vacuum environment eliminates impurities such as oxides and
nitrides
 Minimal Distortion: low distortion means intricate components can be
accurately joined
 Reactive and refractory metals can be welded in vacuum (no
contamination).
 HAZ: Very narrow heat affected zone (HAZ) due to lower heat input per unit
length than in arc welding.
 Shielding Gas: no shielding gas required.
Advantages

17.  Cost: very high equipment cost, the equipment can cost hundreds of thousands
to millions of dollars.
 Complexity: The equipment is complex .In other words, more ways to do it
wrong;
OR
according to Murphy's law;
"if there is a way to do it wrong, someone will do”
 Vacuum: High vacuum (10-3 – 10-6 torr) is inconvenient (difficult).
 Missed jointed: of dissimilar metal can be obtained due to beam deflection.
 Precise alignment of the joints and the gun is required due to small beam size.
Disadvantages