welding method in Friction stir welding industrial used welding method in Friction stir welding

1. J I S H N U U
S 5 M e c h a n i c a l
R o l l N o : 3 5

2. 1.0 INTRODUCTION
According to TWI (The Welding Institute),
Friction Stir welding invented by Wayne
Thomas at TWI Ltd. in 1991 England,
Overcomes many of the problems
associated with traditional joining (welding)
techniques. In short the Friction Stir Welding
is also known as FWS. Since its invention,
the process has received world-wide
attention and today many companies are
using the technology in production, mainly
for joining aluminium alloys. Also FSW is a
process that can be automated. It is also a
cleaner and more efficient process
compared to conventional techniques.

3. 2.0 WORKING PRINCIPLE
 This technique uses Friction as the major
welding resource.
 No filler material is involved.
 Weld is created by,
a) Frictional heating.
b) Mechanical deformation.
 Heat from mechanical energy conversion
a) Linear friction welding.
b) Rotational friction welding.

4. 3.0 FRICTION STIR WELDING
Rotating probe provide
friction heat and
pressure which joins
the material.
Sufficient downward
force to maintain
pressure and create
friction heat.
Probe which stir the material.
Shoulder which creates friction heat
and welding pressure
Sufficient downward force to maintain
pressure and to create friction heat

5. 4.0 MICROSTRUCTURE ANALYSIS
A) Unaffected material
B) Heat affected zone (HAZ)
C) Thermo-Mechanically Affected zone (TMAZ)
D) Weld nugget (Part of Thermo-Mechanically affected
zone)
In this microstructure
analysis we can
understand the structural
deformation the welded
part through the Friction
stir welding process.

6. 4.1 MICROSTRUCTURE ANALYSIS
Unaffected material
Unaffected material or parent
material: This is material remote
from the weld, which has not
been deformed, and which
although it may have
experienced a thermal cycle
from the weld is not affected by
the heat in terms of
microstructure or mechanical
properties.

7. 4.2 MICROSTRUCTURE ANALYSIS
Heat affected zone (HAZ): In this region, which clearly will lie closer to the
weld center, the material has experienced a thermal cycle, which has
modified the microstructure and/or the mechanical properties. However,
there is no plastic deformation occurring in this area. In the previous
system, this was referred to as the "thermally affected zone". The term
heat affected zone is now preferred, as this is a direct parallel with the
heat affected zone in other thermal processes, and there is little
justification for a separate name.
Heat affected zone (HAZ)

8. 4.3 MICROSTRUCTURE ANALYSIS
Thermo-Mechanically Affected zone (TMAZ): In this region, the material has
been plastically deformed by the friction stir welding tool, and the heat from the process
will also have exerted some influence on the material. In the case of aluminum, it is
possible to get significant plastic strain without recrystallization in this region, and there is
generally a distinct boundary between the recrystallized zone and the deformed zones of
the TMAZ. In the earlier classification, these two sub-zones were treated as distinct
microstructural regions. However, subsequent work on other materials has shown that
aluminium behaves in a different manner to most other materials, in that it can be
extensively deformed at high temperature without recrystallisation. In other materials, the
distinct recrystallised region (the nugget) is absent, and the whole of the TMAZ appears
to be recrystallised.
Thermo-Mechanically Affected zone (TMAZ)

9. 4.4 MICROSTRUCTURE ANALYSIS
Weld nugget: The recrystallised area in the TMAZ in aluminium alloys has traditionally
been called the nugget. Although this term is descriptive, it is not very scientific. However,
its use has become widespread, and as there is no word which is equally simple with
greater scientific merit, this term has been adopted. A schematic diagram is shown in the
above Figure which clearly identifies the various regions. It has been suggested that the
area immediately below the tool shoulder (which is clearly part of the TMAZ) should be
given a separate category, as the grain structure is often different here. The microstructure
here is determined by rubbing by the rear face of the shoulder, and the material may have
cooled below its maximum. It is suggested that this area is treated as a separate sub-zone
of the TMAZ.
Weld nugget

10. 4.5 MICROSTRUCTURE ANALYSIS
Optical micrographs of regions (a), (b) and (c) of the stir
nugget.

11. 5.0 JOINT GEOMETRIES
It can be used in all
positions :
a) Horizontal
b) Vertical
c) Overhead
d) Orbital

12. 6.0 TOOLS PARAMETERS

13. 6.0 COMMON TOOLS
Self Reacting Pin Tool
Fixed Pin Tool
Adjustable Pin Tool Retractable Pin Tool

14. 7.0 WELDING STEEL USING (FSW)

15. 8.0 SOME OF THE FSW MACHINES
ESAB SuperStir TM machine FW28
ESAB Machine

16. 9.0 ANIMATION OF WELD
•https://www.youtube.com/watch?v=ZpG
fjg6BI5o
•https://www.youtube.com/watch?v=lrAiq
hr9oD4
•https://www.youtube.com/watch?v=BQY
Ldw8W5wE

17. 10.0 ADVANTAGES
 Diverse materials: Welds a wide range of alloys, including previously
un-weld able (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.

18. 11.0 COMPARISION WITH OTHER JOINING
PROCESS
FSW VS Fusion welding
 Improved mechanical properties
 Reduce distortion
 Reduce defect rate
 Parent metal chemistry
 Simplifies dissimilar alloy welding
 Fewer process variables
 Eliminates consumables
 Reduces health hazard

19. 11.1 COMPARISION WITH OTHER JOINING
PROCESS
FSW VS Reveting
 Reduced production time
 Reduced defect rate
 Increase load carrying capacity and
fracture performance
 Eliminates consumables
 Less operator dependent

20. 12.0 DISADVANTAGES
 Work piece must be rigidly clamped.
 Backing bar required (except were self
reacting tool or direct opposed tools
are used).
 Keyhole at the end of each weld.
 Cannot make joints which requires
metal deposition.

21. 13.0 BERRIERS
 Special clamping system required.
 Only for simple joint geometries.
 Licence required from TWI (The Welding
Institute).
 Few application in the construction
industry.
 Corrosion protection is needed.

22. 14.0 FUTURE DEVELOPMENT
 Laser assisted friction stir welding.
 Possible use of induction coil and
other mechanism.

23. 15.0 CONCLUSION
 Good alternate to fusion
welding.
 Advanced technologies are
in the offing.

24. 16.0 REFERANCE
 1) Boldyrev R N and Voinov V P: 'Possible Reasons for the formation of
Extremum of Torque during Heating in Friction Welding'. Weld Prod. No. 1,
1980, pp.10-12.
 2) Godet M: 'The third-body approach: A mechanical view of wear'. Wear,
Vol. No. 100, 1984, pp.437-452.
 3) Singer Irwin L: 'How Third-Body Process Affects Friction & Wear' MRS
Bulletin 1998, 6.
 4) Suery M, Blandin J J and Dendievel R: 'Rheological behavior of two
phase super plastic materials'. Materials Science Forum, Vols. 170-172,
1994, pp.167-176.
 5) Bevington J: 'Spinning tubes mode of welding the ends of wire, rods,
etc, and mode of making tubes'. US patent 463134, 1891.
 6) www.twi.co.uk
 7) The Production Technology by O.P.Khanna.