1. Aluminum Frcition
Welding

2. Contents
• Concept of friction welding.
• Types of friction welding
(Inertia, stir )
• Metallurgy of friction welding.
• Advantages & disadvantages.
• Applications.
.

3. Conceptof friction
• What is Friction Welding?
• Friction welding is a solid-state process (non-fusion) that is
achieved through frictional heat.
• This heat is generated by controlled contact of two
components until material reaches its plastic state, at which
time plasticized material begins to form layers that intertwine
with one another.
• The friction welding machine controls this contact through a
series of unique parameters for rotational speed (rpm’s), axial
force and time.
• Once these parameters are established, they are recorded,
stored and then repeated with each cycle of the machine

4. Types offriction welding
Friction welding
Inertia Stir

5. Types offriction welding
Inertia friction welding:
In Inertia Welding, one of the
workpieces is connected to a
flywheel and the other is
restrained from rotating. The
flywheel is accelerated to a
predetermined rotational speed,
storing the required energy. The drive motor is disengaged and
workpieces are forced together by the friction welding force.

6. Types offriction welding
Stir Friction Welding:
The frictional heating causes a softened
zone of material to form around the probe.
This softened material cannot escape as it
is constrained by the tool shoulder.
As the tool is traversed along the joint
line, material is swept around the tool
probe between the retreating side of the
tool (where the local motion due to
rotation opposes the forward motion) and
the surrounding undeformed material.

8. Advantages & Disadvantages
Advantages of Friction Welding:
• Strong welds for all geometries.
• Narrowest heat affected zones .
• Short weld times save you time and money.
• There is no melting ,hence no solidification defects occur, gas
porosity , and segregation .
• Easy to manage with only two quality control parameters - RPM and
Pressure.
• Used for some alloys which are not fusion weldable like , AL 7075.
• Limitless panel length and width.
• Join dissimilar alloys.

9. Advantages & Disadvantages
Disadvantages:
• Worm holes
• Oxide film due to Zn affecting surface
tension of weld pool reduced diffusion.
• Cannot easily be used for making fillet
welds.

10. Metallurgy
• Deformation mechanisms:
(Boundary diffusion- recrystallization )
• Strengthening mechanisms:
-Fine graining

11. Metallurgy
Mechanical Properties:
1-Strength
• Higher after process due to :
-fine graining.
ơ 𝑦 = ơ0+
𝑘
𝑑
-increase of welding speed.

12. Metallurgy
2-Hardening:
• higher due to Precipitation hardening
By aging.

13. Applications
Space shuttle technology:
• Using frictional stir welding in external tanks
because of :
-high strength.
-low defects.
• Replacing AL 2219 with
AL-LI 2195 reducing 3400kg .