1. Welding

2. ELECTRON BEAM WELDING
•The electron beam gun has a tungsten filament which is
heated, freeing electrons.
•The electrons are accelerated from the source with high
voltage potential between a cathode and anode.
•The stream of electrons then pass through a hole in the anode.
The beam is directed by magnetic forces of focusing and
deflecting coils. This beam is directed out of the gun column
and strikes the workpiece.
•The potential energy of the electrons is transferred to heat
upon impact of the workpiece and cuts a perfect hole at the
weld joint. Molten metal fills in behind the beam, creating a
deep finished weld.
Fusion of base metals eliminates the need for filler metals. The
vacuum requirement for operation of the electron beam
equipment eliminates the need for shielding gases and fluxes

5. Advantages
• Maximum amount of weld penetration with the least amount of heat
input reduces distortion
• Electron beam welding often reduces the need for secondary
operations
• Repeatability is achieved through electrical control systems
• A cleaner, stronger and homogeneous weld is produced in a
vacuum
• The electron beam machine's vacuum environment eliminates
atmospheric contaminates in the weld
• Exotic alloys and dissimilar materials can be welded
• Extreme precision due to CNC programming and magnification of
operator viewing
• Electron beam welding frequently yields a 0% scrap rate

6. Disadvantages
• EBW is by far the most costly welding process; the equipment
can cost hundreds of thousands to millions of dollars.
• EBW requires a vacuum chamber containing a hard vacuum.
• Only small to medium size items can be welded. Though the
welding itself can be done very fast, overall EBW is time
consuming.
• The equipment is complex and there are quite a few process
variables involved.

7. Laser beam welding

8. LASER BEAM WELDING
• A laser beam is produced inside of the Ruby Crystal. The Ruby Crystal is made of
aluminium oxide with chromium dispersed throughout it.
• Which is forming about 1/2000 of crystal, this less than natural ruby. Silver coated
mirrors are fitted internally in the both side of crystal. The one side of mirror has a
tiny hole, a beam is come out through this hole.
• A flash tube is placed around the Ruby Crystal, which is filled with xenon inert gas.
• The flash is specially designed such as which is made flash rate about thousands
flashes per seconds.
• The electrical energy is converted into light energy, this is worked by flash tube.
• The capacitor is provided for storage the electrical energy and supply the high
voltage to flash tube for performed appropriately.

9. • The electrical energy discharged from capacitor and xenon transform the high
energy into white flash light rate of 1/1000 per second.
• The chromium atoms of Ruby Crystal are excited and pumped into high energy.
Due to heat generating the some of this energy is lost.
• But some light energy reflected mirror to mirror and again chromium atoms are
excited until loss their extra energy simultaneously to form a narrow beam of
coherent light. Which is come out through the one end tiny hole of crystal’s mirror.
• This narrow beam is focused by a optical focusing lens to produce a small intense
of laser on the job.

10. Advantages
• Single pass weld penetration up to 3/4” in steel
• High Travel speed
• Materials need not be conductive
• No filler metal required
• Low heat input produces low distortion
• Does not require a vacuum

11. Disadvantages
• High initial start-up costs
• Part fit-up and joint tracking are critical
• Not portable
• Metals such as copper and aluminum have high
reflectivity and are difficult to laser weld
• High cooling rates may lead to materials problems

12. Solid state welding
• A group of welding processes which produces
coalescence at temperatures essentially below the
melting point of the base materials being joined,
without the addition of brazing filler metal.
• Pressure may or may not be used. These processes are
sometimes erroneously called solid state bonding
processes: this group of welding processes includes
cold welding, diffusion welding, explosion welding,
forge welding, friction welding, hot pressure welding,
roll welding, and ultrasonic welding.

13. • Solid state welding includes some of the very oldest of
the welding processes and some of the very newest.
Some of the processes offer certain advantages since
the base metal does not melt and form a nugget.
• The metals being joined retain their original properties
without the heat-affected zone problems involved
when there is base metal melting.
• When dissimilar metals are joined their thermal
expansion and conductivity is of much less importance
with solid state welding than with the arc welding
processes

14. Cold welding
• A solid state welding process which uses pressure at room
temperature to produce coalescence of metals with substantial
deformation at the weld.
• Welding is accomplished by using extremely high pressures on
extremely clean interfacing materials. Sufficiently high pressure can
be obtained with simple hand tools when extremely thin materials
are being joined.
• When cold welding heavier sections a press is usually required to
exert sufficient pressure to make a successful weld.
• Indentations are usually made in the parts being cold welded. The
process is readily adaptable to joining ductile metals.
• Aluminum and copper are readily cold welded. Aluminum and
copper can be joined together by cold welding

15. • At least one of the metals must be
ductile without excessive work-
hardening.
• Total absence of applied heating.
• Dissimilar metals can be joined.
• Surface preparation is important.
Characteristics of Cold Welding

16. • A solid-state welding process
that produces coalescence of
the faying surfaces by the
application of pressure at
elevated temperature.
• The process does not involve
macroscopic deformation, or
relative motion of the
workpieces.
• A solid filler metal may or may
not be inserted between the
faying surfaces.
Work pieces
Schematic representation of
diffusion welding using
electrical resistance for heating
A
B
Force
Definition of Diffusion Welding

17. • 1st stage
– deformation forming
interfacial boundary.
• 2nd stage
– Grain boundary migration
and pore elimination.
• 3rd stage
– Volume diffusion and pore
elimination.
asperities come
into contact.
2nd stage grain
boundary migration
and pore elimination
1st stage deformation
and interfacial boundary
formation
3rd stage volume
diffusion pore
elimination
Diffusion Welding Working Principles

19. A solid state welding process in which
coalescence is produced at the faying surfaces
by the application of high frequency vibratory
energy while the work pieces are held
together under moderately low static
pressure.
Definition of Ultrasonic Welding

20. • A static clamping force is
applied perpendicular to the
interface between the work
pieces.
• The contacting sonotrode
oscillates parallel to the
interface.
• Combined effect of static and
oscillating force produces
deformation which promotes
welding.
Anvil
Mass
Sonotrode
tip
Clamping
force
wedge Transducer
Force
workpiece
Ultrasonic Welding Mechanism
10-75 KHz

21. Ultrasonic Welding Power Generation
• Electrical power of 60
Hz is supplied to the
frequency converter.
• The frequency
converter converts
the required 60 Hz
signal to the welding
frequency (from 10 to
75 kHz).
Electrical
energy
Frequency
converter
Vibratory
transducer
Transducer
Power Generation

22. 2/3
)HT(KE 
Where:
E = electrical energy, W*s (J)
k = a constant for a given welding system
H = Vickers hardness number of the sheet
T = thickness of the sheet in contact with the sonotrode tip, in. (mm)
Power Requirements
The constant “K” is a complex function that appears to involve primarily the
electromechanical conversion efficiency of the transducer, the impedance
match into the weld, and other characteristics of the welding system.
Different types of transducer systems have substantially different K values.

23. • No heat is applied and no melting occurs.
• Permits welding of thin to thick sections.
• Welding can be made through some surface
coatings.
• Pressures used are lower, welding times are
shorter, and the thickness of deformed
regions are thinner than for cold welding.
Advantages of Ultrasonic Welding

24. • The thickness of the component adjacent to
the sonotrode tip must not exceed relatively
thin gages because of power limitations of the
equipment.
• Process is limited to lap joints.
• Butt welds can not be made because there is
no means of supporting the workpieces and
applying clamping force.
Limitations of Ultrasonic Welding

25. • Friction welding is a
solid state joining
process that produces
coalescence by the
heat developed
between two surfaces
by mechanically
induced surface
motion.
Definition of Friction Welding

27. • One of the workpieces is
attached to a rotating
motor drive, the other is
fixed in an axial motion
system.
• One workpiece is rotated
at constant speed by the
motor.
• An axial or radial force is
applied.
Continuous Drive
Workpieces
Non-rotating viseMotor
Chuck
Spindle Hydraulic cylinder
Brake
Continuous Drive Friction Welding

29. • The work pieces are
brought together under
pressure for a predeter-
mined time, or until a
preset upset is reached.
• Then the drive is
disengaged and a break
is applied to the
rotating work piece.
Continuous Drive
Workpieces
Non-rotating viseMotor
Chuck
Spindle Hydraulic cylinder
Brake
Continuous Drive Friction Welding

30. Friction Stir
Welding
• Parts to be joined are clamped
firmly.
• A rotating hardened steel tool
is driven into the joint and
traversed along the joint line
between the parts.
• The rotating tool produces
friction with the parts,
generating enough heat and
deformation to weld the parts
together.
Butt welds
Overlap welds

31. Friction Stir Welding
Step -1
Step -2
Step -3
Step -4
clamping
force
Clamping
force

32. Plasma welding

34. WHAT IS PLASMA?

37. Copper introduction
• Copper is second only to iron and steel in
commercial importance.
• It is of brownish red colour and posses the
following properties
• Resistance to corrosion.
• Non magnetic properties.
• Easy to work ,it is ductile and malleable
• High thermal and electric conductivity

38. • Compared to with ferrous materials ,copper
based material have
• High thermal conductives
• Greater thermal expansion coefficient, and
some cases
• Susceptibility to hot cracking
• Oxidation
• Fluidity of molten copper

39. • Higher thermal conductivity necessitates high heat
input into the parental metal to raise the temperature
sufficiently to produce the fusion desirable for most
welding processes.
• High input heat is provide by
• High welding current
• Nozzles tips of larger size
• Copper has high thermal expansion coefficients are
responsible for introduction of residual stresses in and
around the joint
• Preheating helps to minimize the thermal co efficient
of expansion

40. • Suitable fixture are used to reduce the distortion
in welding materials.
• Copper has relatively low strength above 500deg
,therefore cracking may occur where severe
stresses are introduced into the weldment.
• Copper has a tendency to absorb oxygen in
molten state .
presence of oxygen tends to reduce the melting
point and corrosion resistance and decrease the
mechanical properties

41. • Usage of flux or inert gas is necessary to avoid
the oxidation.
• Greater welding speeds should be used for
copper and its alloys than is practical for steel

42. Explosion welding (EXW)
• A solid state process where welding is
accomplished by accelerating one of the
components at extremely high velocity through
the use of chemical explosives. This process is
most commonly utilized to clad carbon steel plate
with a thin layer o f corrosion resistant material
(e.g., stainless steel, nickel alloy, titanium,
or zirconium). Due to the nature of this process,
producible geometries are very limited. They
must be simple. Typical geometries produced
include plates, tubing and tubeshe