Friction stir welding is a solid state joining technique invented in 1991 as an alternative to fusion welding. It involves a rotating cylindrical tool that is plunged into aluminum or other metal workpieces, generating frictional heat below the melting point and allowing material flow. Key parameters include tool design, rotation speed, travel speed, tilt, and plunge depth. Compared to fusion welding, FSW reduces defects, distortion, and hazards while improving mechanical properties. It has applications in shipbuilding, aerospace, transportation, and microfabrication.
Cara Menggugurkan Sperma Yang Masuk Rahim Biyar Tidak Hamil
Friction stir welding (fsw)
1. Friction Stir Welding (FSW)
Presented By:
Agha Zeeshan Ali E12-328
M. Farhan Ashraf Butt E12-329
Muhammad Qasim E12-327
2. Contents
• Introduction
• Principle of FSW technique
• Microstructural features
• Important welding parameters
• Comparison
• Advantages
• Industrial applications
• Modern development
• Conclusion
• reference
3. Introduction
• Invented by TWI in 1991.
• It overcomes many problems associated with the
conventional joining techniques.
• FSW requires low energy input, capable of producing
very high strength welds in wide range of materials at
low cost.
• FSW process takes place in the solid phase below the
melting point of the materials to be joined.
4. Working principle of FSW
• A cylindrical tool with a
profiled probe is rotated
and plunged slowly into
the joint line between the
two work pieces welded
together.
• Frictional heat is generated
between the wear resistant
welding tool and the
material of the work
pieces.
• This frictional heat is
without reaching the
melting point allows the
travelling of the tool along
the weld line.
5. Microstructural Features
• Friction stir weld consist of three main zones
1. Nugget, stir zone.
2. Thermo-mechanically affected zone (TMAZ).
3. Heat affected zone.
• The stir (nugget) zone is a region of heavily deformed material
that roughly corresponds to the location of the pin during
welding. The grains within this zone are roughly of equal size
and often smaller than the size of the grain of the parent
material.
6. Microstructural features
• TMAZ occurs on either sides of the stirred zone. In this region
the strain and temperature are lower and the effect of
welding on the microstructure is correspondingly smaller.
• HAZ is common to all welding processes. This region is
subjected to a thermal cycle but is not deformed during the
welding. The temperatures are lower than those in the TMAZ.
• The three zones possess different mechanical properties.
8. Important welding parameters
• Tool Design
The design of the tool is a critical factor as a good tool can
improve the quality and welding speed.
Tool is strong, tough, hard wearing at welding
temperatures.
Have good oxidation resistance and thermal conductivity.
H13 steel has proven perfectly acceptable for welding AL
alloys but more advance tool materials are necessary for
more high demanding applications.
9. Important welding parameters
• Tool rotation and speed
The two tool speeds are considered in FSW; how fast the
tool rotates and how quickly it travels along the interface.
It can be said that increasing the tool rotation speed and
decreasing the travelling speed will result in a hotter weld.
In order to produce a successful weld it is necessary that
the material surrounding the tool is hot enough to enable
the extensive plastic flow required and minimize the forces
acting on the tool.
10. Important welding parameters
If the material is too cold then voids or other flaws may be
present in the stir zone.
These competing demand lead onto the concept of a
“processing window”. Processing window is basically the range
of processing parameters that will produce a good quality
weld.
Within this window the resulting weld will have a sufficiently
high heat input to ensure adequate material plasticity but not
so high that the weld properties are deteriorated.
11. Important welding parameters
• Tool tilt and plunge depth
The plunge depth is defined as the depth of the lowest
point of the tool below the surface of the welded plate and
has been found to be a critical parameter for ensuring weld
quality.
Plunging the tool below the plate surface increases the
pressure below the tool and helps ensure adequate forging
of the material.
12. Important welding parameters
Tilting the tool 2-4 degrees such that the rear of the tool is
lower than the front has been found to assist the forging
process.
Variable load welders have been developed to automatically
compensate the changes in the tool displacement and tilting.
13. Comparison
• FSW vs Fusion welding
Good mechanical properties by weld at below MP of
the workpiece
Reduce distortion
Reduce defect rate
Simplifies dissimilar alloy welding
Eliminates consumables
Reduces health hazards and no weld pool
14. Advantages
• Ability to join materials that are difficult to fusion weld for
example Al, Mg and Cu alloys.
• FSW can use purpose designed-equipment or modified
existing machine tool technology.
• The process is usually automatic and adaptable for robot use.
• No filler or consumables are required in the process.
• Can operate in all positions.
• Process is energy efficient.
15. Advantages
• Excellent mechanical properties in fatigue, tensile and bend
tests.
• No gas shielding for welding aluminum.
• Low environmental impact.
• Low health hazards.
16. Industrial applications
• Shipbuilding and Marine construction
The shipbuilding and marine industries are two of the
first sectors that have adopted the process for
commercial applications.
The process is suitable for the following applications:
• Panels for decks.
• Hulls and superstructure.
• Helicopter landing platforms.
• Refrigration plant.
17. Industrial applications
• Aerospace industry
FSW offers advantage compared to riveting and machining
from solid, such as reduced manufacturing costs and weight
savings.
• Railway industry
The commercial production of high speed trains made from Al
extrusions which may be joined by friction stir welding.
18. Modern Developments
• Micros Friction Stir Welding
It is the adaption of the friction stir welding (FSW) to materials
with thickness of 1000μm or less.
This technique has the ability to join wide range of materials
without the use of fluxes, shielding gases and without post
weld cleaning.
It is especially useful in joining dissimilar materials .
Applications such as joining of thin walled structures,
electrical, electronic and micro mechanical assemblies.
19. Conclusion
• FSW opening up new areas of welding daily.
• No distortion, spatter and fumes.
• Welding at below MP of workpiece.
• Good forging action by tool.
• Create high strength weld in hard materials.
• It is alternative to fusion welding.
