(1) The document discusses heat generation during friction stir welding using a homemade friction stir welding tool. An infrared video camera was used to capture the heat generation between the tool and workpiece, showing temperatures ranging from 380-450°C. (2) A numerical model was developed to simulate the heat generation during friction stir welding. The model found that parameters like normal force, welding speed, spindle speed, and friction coefficient can be adjusted to control the heat generation. (3) The research concluded that a homemade friction stir welding tool was successfully designed and used for friction stir welding, with only minor defects observed. Heat generation maps from the numerical model matched well with experimental results.

1. Heat Generation Performance of a
Homemade Friction Stir Welding
Tool
Irfan Hilmy, ihilmy@iium.edu.my
Manufacturing and Material Dept.,
Faculty of Engineering IIUM
To be presented at
First International Manufacturing Engineering Conference (IMEC 2013)
Organized by
The Faculty of Manufacturing Engineering, Universiti Malaysia Pahang
1 July 2013
Link to the Paper:
http://bit.do/hfswt

2. Background
Friction stir processing is an emerging surface–engineering technology
based on the principles of friction stir welding (FSW).
Friction stir welding is a relatively new joining process, invented at The
Welding Institute (Cambridge, UK) in 1991 and developed initially for
aluminum alloys. Since then FSW has rapidly evolved and has opened
up a variety of research channels.
It is a solid-state joining technique that is energy
efficient, environment friendly, and versatile. It is being
touted as the most significant development in metal
joining in the last decade.

3. Objective
It has been documented that heat is generated during
friction stir processing. The amount of heat
generated between the shoulder and the work piece
during friction stir processing dictates the quality of
the processed zone.
Hence understanding the distribution of heat and
obtaining the temperature contours will assist in
understanding the general process of friction stir
processing.

4. FSW in the shipbuilding industry
The first commercial application of friction stir welding concerned the manufacture
of hollow aluminium panels for deep freezing of fish on fishing boats.
These panels are made from friction stir welded aluminium extrusions.
The minimal distortion and high reproducibility make FSW both
technically and economically a very attractive method to produce these stiff
panels.
FSW panel for pre-pressing of fish
blocks before quick freezing. The
panel is welded from both sides
Prefabricated FSW panel for half the
width of the superstructure of a cruise
liner
Portable FSW machine on the
shipyard of the Research
Foundation Institute in Cairns,
Australia

5. FSW in the airspace industry
A longitudinal
welding
machine, plus
handling equipment
for welding of fuel
tanks for the Delta
II programme of
space rockets.
A complete plant designed for
circumferential welding of fuel
tanks, also including a friction plug
welding unit.

6. FSW in the automotive industry
Mazda uses FSW to attach steel
studs to the MX-5 Miata’s aluminum
inner-trunk panel.
The new Honda Accord’s front subframe,
which carries the engine and some
suspension components, is made of
aluminum and steel halves. The details are
proprietary, although Honda has said this is
the first use of continuous, or linear, FSW
in a bi-metal structural component of a
production vehicle.

7. FSW Mechanism

8. FSW Mechanism (2)

9. Standard FSW tool
Basic FSW tool pin profiles
Advanced FSW tools developed at The Welding Institute, Cambridge

10. Fabrication of homemade tool
FSW tool, initial
design
final product

11. Testing and Heat measurement
Two pieces of aluminum alloy plate with the dimension 50x50
mm were prepared. To capture the heat, infra red video camera was
used. The overall setup is shown in the left Figure while the heat generation
as captured by infra red video camera is shown in the right Figure. From the
video result, any particular point of interest (POI) can be determined. For this
purpose, the point located at the surrounding of the contact region was
observed

12. Numerical model
Previous numerical models were developed by many
researchers. Among them are Colegrove[5], Vepakomma[7],
Chao[8], Wong[9] and Shah[10]. Heat generation analysis of a
solid model became the focus of this research. The finite-
element model of FSW process was constructed as shown in
the Figure

13. Heat Generation Formula
where qshoulder
is local heat flux and qpin
is surface heat source from the pin, µ is friction
coefficient, Fn
is normal force, τ is average shear stress as a function of temperature, As
is
shoulder contact area with the specimen, ω is spindle speed, r is distance from an arbitrary
point in the shoulder area, rp
is pin radius, ε is surface emissivity, hup
, hdown
are natural
convection constant of top and bottom side respectively and σ is Steffan-Boltzman constant.
( )
( )



≥
<
=
melt
meltsn
shoulder
TT
TTrAF
Trq
;0
;
,
ωµ
( )
( )
( )TrTq ppin τω
µ
µ
2
13 +
=
( ) ( )44
0 TTTThq ambupup −+−= εσ
( ) ( )44
0 TTTThq ambdowndown −+−= εσ
(1)
(2)
(3)
(4)

14. FSW Tool: Standard

15. Property of Homemade Tool

16. Work piece property

17. Result and Discussion
Considering the file size, data was
recorded only in one minute for each
attempt. The transient phase of
arising temperature was not
captured. Fig. 5(inset) shows heat
recorded at the point of interest of
four FSW process. Range of
temperature was recorded between
380O
C - 450O
C.
From the simulation, it was found that by changing the following parameters:
(1) normal force, (2) welding speed, (3) spindle speed and (4) friction coefficient,
heat generation can be controlled. Parameter number one to three are related to
the milling machine while the last one depends on the contact surface between
tool and work piece.

18. Conclusions
From this research, some conclusions have been made
and presented as follows:
1.Homemade FSW tool has been designed
and fabricated.
2.FSW process using homemade welding tool and
utilizing the heavy load milling machine have been
performed successfully with minor defect.
3.Heat generation map of a work piece material has
been produced using the numerical model.
4.Good agreement between experimental and numerical
investigation with error less than 5% have been made.

19. Thank you very much for
your attention