Introduction,Main components,working,pros and cons,applications,schematic,research article based,Heat affected zones,Microstructure changes

1. FRICTION STIR
WELDING
-Submitted by
N.V.A.S.M.SASTRY
9820010002
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2. Introduction • Permanent joining technique
• Categorized under solid state welding
• Uses heat produced by friction
• Combines mechanical force and heat to
join
• Used mostly to join Aluminum alloys.
• Predominantly used in Automobile
industries.
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3. Schematic Of
Friction Stir
Welding
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4. Main
components
of the
system
• Probe
• FSW tool
• Clamps
• Shoulder
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5. Working
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• The probe is set into the FSW tool
• FSW tool rotates and penetrates into
workpiece.
• Due to combined rotation and friction
heat is produced.
• Temperature is less than melting
temperature.
• Spinning probe mixes the softened
metals.
• Softened metals mixes with other
material
• Metals get welded on cooling.
• Rotational and linear speeds
influences the weld joint.

6. Probe Of FSW
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• Main component of
FSW.
• Various types are used
for various situations
• Selection depends on
material parameters.
• High speed steel tool
is used for aluminum .
• For steel and tungsten
alloys iridium alloy
based tool Is used.

7. HAZ
1.Weld Nugget
2.TMAZ
3.HAZ
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8. Microstructural
changes
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Stir Zone (weld nugget): The grains get elongated and
becomes equiaxed and recrystallized.The recrystallization is
due to severe plastic deformation in the zone.
TMAZ: The grains inTMAZ has also become
equiaxed and recrystallized.Large grains are surrounded by
small grains which showes mesh structure.
HAZ: The heat affected zone is adjacent toTMAZ and
outside the tool shoulder. In HAZ material is affected by heat
generated due to friction between material and tool.The grain
structure is similar to base metal case.
Base metal: In base metal grains are elongated and varying
size which are randomly distributed

9. Process
parameters
• Tool rotation speed (TRS)
Tells about the speed and direction of rotation of the
tool.It should be optimum.
• Tool transverse speed
The tool traverse spced should be minimum in order to produce a
successful weld and to produce required plastic flow.
• Tool tilt Angle
Tool should be tilted to enable a gradual increase of forging
pressure.
• Plunge depth
The plunge depth is shoulders lowest point depth. It can be seen
below the surface of the welded plate. It helps to ensure quality of
the weld.
• Axial force
The force that is applied on the materials.It helps in
bonding the metals properly. 9

10. PRO’S AND CON’S
PRO’S
• Reduced distortion
• Reduced residual stresses
• Possibility to join different
materials
• No need of surface pretreatment
• Localized Heating
• High strength of welded joints
• Automation is easy
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Con’s
• High investment cost’s
• Work piece must be rigidly
clamped
• Key hole at the end of each weld.
• Can’t be used for non-forgeable
materials
• Can’t be used in weld joints where
metal deposition is required.

11. Applications
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1.Aerospace
industries
2.Nuclear waste
storage cans
3.Automobile
industries
4.Marine industries
5.Railway industries

12. Inferences
from the
research
paper
• As the speed of welding and plate thickness increases
tool durability decreases.
• On dissimilar metals maximum tensile strength is
obtained at tool rotation speed of 2000rpm,weld speed
of 37mm/min and axial force of 0.75kn
• larger Shoulder diameter causes increase in the weld
pitch with a joint efficiency of 78%.
• Magnesium alloys can be welded defects free at an
axial force of 3 kn.
• Polyethene plates can be welded at 90% joint
efficiency at 930 rpm/min of tool and travel speed of 25
mm/min
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13. Reference Research article details
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