FRICTION_STIR_WELDING

1. SEMINAR PRESENTATION
ON
FRICTION STIR WELDING
Presented By:
Satyam Maurya
Final B.Tech. Mechanical
Engineering
200110055
Submitted To:
Dr. Nishant Kumar Singh
Professor
Mechanical Engineering
Department
Department Of Mechanical Engineering
School Of Engineering
Harcourt Butler technical university, Kanpur
Nawabganj, Kanpur (U.P.)
Session 2023-24

2. Contents
 Introduction
 Types of FSW
 Steps in Friction Wielding Process
 Principle of operation
 Microstructure
 Process parameters
 Types of tool bits in FSW
 Types of joints
 Set Up
 Comparison with other joining processes
 Application areas
 Advantages
 Disadvantages

3.  It is a solid-state welding and it
is performed using heat
generated from the friction of a
rotating tool.
 This process is invented and
patented by The Welding
Institute (TWI) in the United
Kingdom in 1991 for butt and
lap welding of metals and
plastics.
 The maximum temperature
rises is about 0.8 of the melting
point temperature of the base
materials.

4.  Friction Stir Welding (FSW) can
be considered as a
“green technology”
because no gases are evolved
during the process. Also, there are
no toxic fumes or smoke produced
during or after the welding
process.
 The process is energy
efficient and environmentally
friendly.
 Compared to other conventional
fusion welding methods, FSW
offers a number of advantages.

6. Steps in Friction Wielding Process
1. Positioning plates
2. Pin penetrating in to plate
3. Tool travel
4. Pin removal

8. The process involves plunging a non-consumable tool
between the abutting edges of the two plates to be butt welded,
traversing the tool along the joint line (at a
predetermined rotational speed and feed rate), and at the end,
the tool is retracted from the weld. The fundamental
difference between conventional welding techniques and the
solid-state Friction Stir Welding (FSW) technique is that no
heat is added to the ‘system’; instead heat is generated
internally by means of friction between the tool-material
interface resulting in the plastic deformation of the material
around the stir zone.
Principle of Operation

9. FSW process involves four phases which are:
1) Plunging phase,
2) Dwelling phase
3) Welding phase, and
4) Exit or retract phase.
Plunging phase: The process starts with rotating tool pin
or probe thrusting onto the configured work materials
under a constant axial load to generate friction heat.
• In this phase the temperature between rotating tool and
the workpiece increases
• The process continue until the temperature at the
immediate contact of the rotating tool and the work
material increased to a temperature which causes the
work material to soften, plasticized and significantly lose
its strength.

10. • The end of the plunging phase is signified by the
sound contact of the rotating tool shoulder with the
immediate work material surface.
 Dwelling phase : Here the rotating tool is allowed to
dwell for a period of time, causing the temperature to
increase further, up to its hot working temperature.
• The heat generated from frictional work is greatly
dependent on the relative increase of contact surface area
as well as the relative speed.
 Retract phase : At the end of FSW process, the rotating
tool is retracted away from the work material leaving a
cylindrical hole mark that once occupied by the tool pin.
• The cylindrical hole may be filled with filler material at the
end of the welding process but the most common method
used is by introducing dummy material prior the exit
phase.

11. Microstructure:
A. Unaffected material
B. Heat affected zone (HAZ)
C. Thermo-mechanically affected zone (TMAZ)
D. Weld nugget (Part of thermo-mechanically affected
zone)

12. Process Parameters
FSW involves complex material movement and plastic
deformation. Welding parameters, tool geometry, and joint
design exert significant effect on the material flow pattern
and temperature distribution.
• Tool rotational speed
• Tool transverse speed
• Tool tilt angle
• Tool plunge depth
• Tool plunging force
• Tool geometry
• Tool shoulder diameter
• Pin length
• Pin geometry

13. STRESS ANALYSIS :
• The tool pin, the weakest component of the tool, experiences
severe stresses at high temperatures due to both bending moment
and torsion.
• It is shown that the optimum tool pin geometry can be determined
from its load bearing capacity for a given set of welding variables
and tool and work-piece materials.
• The traverse force and torque during friction stir welding are
computed using a three-dimensional heat transfer and viscoplastic
material flow model considering temperature and strain rate-
dependent flow stress of the work-piece material.
• These computed values are used to determine the maximum shear
stress experienced by the tool pin due to bending moment and
torsion for various welding variables and tool pin dimensions.
• It is shown that a tool pin with smaller length and larger diameter
will be able to sustain more stress than a longer pin with smaller
diameter.
• The proposed methodology is used to explain the failure and
deformation of the tool is contributed by low values of factor of
safety in an environment of high temperature and severe stress.

14. Tool Material used according to the Welded Material :
Size of Material that can be welded :
Currently the sizes of the clamping arrangements determine the size of
welded structure and, although length of plate is no longer a problem,
the plate being passed between the clamps after welding to allow
location and clamping of the next section, the actual width of the
clamps must be of a finite size so there is a restriction in the maximum
width of plate Producible.
Example : Perhaps the whole plate for a ship’s hull can be produced in
one piece and then fabricated to shape.

15. Traditional tool bit Tool bits for other materials
Tool bits used in FSW:

17. It can be used in all
positions,
Horizontal
Vertical
Overhead
Orbital

18. Figure shows Orbital type of weld.

20. Set Up

21. Friction Stir Welding Machine

22. Comparison with other joining processes
FSW v/s Fusion Welding FSW v/s Riveting
» Improved Mechanical
Properties
» Reduced Distortion
» Reduced Defect Rate
» Parent Metal Chemistry
» Simplifies Dissimilar
Alloy Welding
» Fewer Process Variables
» Eliminates Consumables
» Reduces Health Hazard
» Reduced Part Count
» Reduced Production
Time
» Reduced Defect Rates
» Increase in Load
Carrying Capability
» Improved Fracture
Performance
» Eliminates Consumables
» Less Operator
Dependent

23. Application areas:
FSW is widely used in
the following industries,
• Aero space
• Civil Aviation

24. • Automotive
• Ship building

25. • Floor panels for bullet trains
• Inserts for nuclear fuel
Preliminary trails using a Friction Stir Weld method
for near net-shape manufacture and three-
dimensional material processing show promise, but
much work will be required to develop and perfect the
technique.

26. Advantages:
 Diverse materials: Welds a wide range of alloys, including
previously un- weldable (and possibly composite materials).
 Durable joints: Provides twice the fatigue resistance of fusion
welds.
 Versatile welds: Welds in all positions and creates straight or
complex-shape welds.
 Retained material properties: Minimizes material distortion
 Safe operation: Does not create hazards such as welding fumes,
radiation, high voltage, liquid metals, or arcing.
 No keyholes: Pin is retracted automatically at end of weld.
 Tapered-thickness weld joints: Pin maintains full penetration.

27. Disadvantages:
 Work pieces must be rigidly clamped.
 Backing bar required (except where self-reacting tool or
directly opposed tools are used).
 Keyhole at the end of each weld.
 Cannot make joints which required metal deposition (e.g.
fillet welds).

28. Conclusions:
 FINALLY, FSW IS AN ENVIRONMENTAL FRIENDLY
MANUFACTURING PROCESS BEING USED AND PRESENTLY
UNDERGOING FURTHER RESEARCH FOR BETTER
UTILIZATION.


29. THANK YOU