The document summarizes a presentation on friction stir welding of pipes. It discusses the challenges of experimental procedures for friction stir welding pipes including producing good quality welds and eliminating keyhole defects. It describes the methodology used including using a vertical milling machine with a tapered tool profile. It outlines the welding parameters tested and experimental results including visual inspections showing smooth and rough welds. Microhardness tests showed highest values in the stir zone. Microstructures revealed grain changes in the stir, thermomechanically affected, and heat affected zones. Eliminating the exit hole defect is discussed using a sacrificial element. The conclusion is that taper tool profile produced good quality welds and exit holes can be addressed.

1. MAJOR PROJECT PRESENTATION
FRICTION STIR WELDING OF PIPES
PRESENTED BY GROUP PI04
HASHMATULLAH IBRAHIMI | ASHIF ALI MIKRANI | SUBED SATYAL | FARZAN ATHAR HASHMI
UNDER THE GUIDANCE OF
PROF. ARSHAD NOOR SIDDIQUE
DEPARTMENT OF MECHANICAL ENGINEERING
JAMIA MILLIA ISLAMIA
NEW DELHI - 110025

2. PROBLEM STATEMENT
TO IDENTIFY CHALLENGES WITH EXPERIMENTAL PROCEDURE ON FRICTION STIR
WELDING OF PIPE WITH A FOCUS TOWARDS
PRODUCING GOOD QUALITY PIPE WELDS
⮚ ELIMININATION OF KEY HOLE DEFECT

3. METHODOLOGY
To carry out FSW on pipes a vertical milling
machine is set up with a suitable fixture according to
the magnitude of forces that will be generated during
the process.
 For pipes the tool profile is suggested as per our
findings to be tapered or conical to ensure reduced
axial load during plunge stage and a suitable
diameter is to be selected so that the temperature
requirements are fulfilled.
Parameters such as traverse speed are decided
corresponding to the motor torque and power
specifications.

4. CONT’D
 The major challenges come with FSW of pipe
welding is the key hole defect, as this portion is
counted for stress concentration region which
tend to easily break or in case of pipe welding
licking of fluid.
 Irregularities of pipe during welding procedure
due to vibration.

5. EXPERIMENTAL PROCEDURE
TOOL MATERIAL : HSS ( HIGH SPEED STEEL )
WORKPIECE MATERIAL : ALUMINIUM ALLOY (AA-6063)

6. WELDING PARAMETERS
 For pipes the tool profile is suggested as
per our findings to be tapered to ensure
reduced axial load during plunge stage.
 The Tool Rotation is selected to provide
better stirring effect.
 Proper Shoulder Diameter ensures correct
heat input and material flow.
 Welding speed or transvers speed is 1.25
rev/min for all the experiments.

7. WORK CHAPTER 1 - VISUAL INSPECTION
• Visual inspections were the first performed examinations. The top surface were examined for any defect and quality of weld.
• The FSW1 and FSW4 give smooth weld surface with some lateral flash; meanwhile FSW2 and FSW3 show rough weld surface
condition.
FSW1 (Smooth weld surface) FSW2 (ROUGH SURFACE)

8. • With the Use of tapered tool pin with less RPM of tool rotation gives Good weld while using
cylinder tool pin required high RPM of rotation.
FSW3
(ROUGH WELD SURFACE WITH LATERAL FLASH)
FSW4
(SMOOTH WELD SURFACE WITH SOME LATERAL
FLASH)

9. WORK CHAPTER 2 - MICRO HARDNESS
The micro-hardness distribution is shown in fig (a,b,c,d).
The micro-hardness investigation for all samples is done
using Vickers hardness testing machine.
The hardness is different in the three zones mentioned
above (SZ, TMAZ, and HAZ). As the deformation occurs
due to the mechanical force and thermal energy in FSW
process
A specimen is cut through Electric Discharge
Machine (EDM) for micro-hardness and
microstructure analysis.
(a) (b)

10. A drop of micro-hardness is
observed on TMAZ of all the
samples due to orientation of grain
from stir zone to TMAZ and also
due to the extended plastic
deformation and absence of
dynamic recrystallization.
The maximum value observed for
micro-hardness in stir zone is 68.9 HV
from sample 4 and this is due to high
RPM
(c)
(d)

11. WORK CHAPTER 3 - MICROSTRUCTURE
• Welds section were polished and etched with a solution consisted of 1.5 ml of HF ,6gm CrO3,15
ml HCL ,10 ml HNO3,42.5 ml Distilled water.
• After the polishing and etching process of the AA6063 the samples are investigated for analysis
of microstructure. Three different zone were observed in the microstructure investigation, namely
the stir zone (SZ), thermo-mechanically affected zone (TMAZ) and the heat affected zone
(HAZ).
FSW1 (HAZ)
FSW1 (TMAZ)
FSW1 STIR ZONE
(SZ)

12. STIR ZONE (SZ) , THERMO-MECHANICALLY AFFECTED ZONE
(TMAZ) AND HEAT AFFECT ZONE (HAZ)
In the Stir Zone or Nugget Zone the
temperature is high as compared to two
other zones. This temperature causes
high deformation and change in grain
size in this region.
Thermo-mechanical affected zone is
located on both side of SZ, and effect by
thermal effects as well as by mechanical
distortion.
FSW1 SZ
FSW1 TMAZ

13. HAZ is only affected by heat as the name suggested and
located on both side of SZ after TMAZ. The heat in this
zone is less than the TMAZ but still this amount heat can
affect the grains
FSW3 (HAZ) FSW4 (HAZ)

14. WORK CHAPTER 4 - EXIT HOLE DEFECT
• In FSW process, after finishing the weld line a
non- consumable stir-pin is pulled out from its
end point location, causing a defect type known
as exit-hole or end point will appear in the final
location of the welding process leaving a
critical hole behind.
• Consequences: Stress concentration, Effects
on mechanical properties & structural integrity
of work piece.

15. PROPOSED METHOD FOR ELIMINATION OF EXIT
HOLE
• We propose prevention of end-hole by using sacrificial
element. This element is made of same material as of
the workpiece.
• The curvature of the surface in the material is chosen
according to the outer diameter of the pipe.
FIXTURE FOR CLAMPING SACRIFICIAL
MATERIAL
• Sacrificial material should be kept on the slot of clamp
and should be tightened by the clamping studs.The
clamp should be given manual movement and should
kept tangentially at the end point of weld.

16. RESULT AND DISSCUSTION
• The FSW shows good results for pipe welding along circumference.
• Selection of parameters play important role in the quality of welds.
• By overcoming the challenges good quality weld can be produced.
• Tool profile along with other parameters can effect the weld quality.

17. CONCLUSIONS
The FSW of AA-6063 is welded in butt joint configuration using different set of parameters and
tool profile, from this study we can conclude that a taper pin profile shows good quality weld this is
due the shape of pin profile that can compensate the temperature difference in inner and outer
surface of the pipe.
A RPM of 710, shoulder of 14mm diameter with taper tool profile can produce a sound good weld
quality as of FSW4.
The pin hole defect can be compensate using a sacrificial piece of the same material as the pipe.
The fixture suggested in this project for holding the sacrificial piece also can be used as support to
overall setup during welding process.

18. SCOPE FOR FUTURE WORK
• As the welding of pipe through the FSW is comparably new technique it has a lot of scope and
future work, many challenges are there and will add to this process as it growth.
• Joining of dissimilar pipe through FSW.
• Solving irregularities and vibrations during welding process due to rotating pipe and other
factors.
• FSW of high temperature materials like Titanium.
• FSW of pipes under water
• Producing best quality welds.

19. 1. D.H.Lammlein, B.T.Gibson, D.R.DeLapp, C.Cox, A.M.Strauss, G.E.Cook, Friction Stir Welding of Small Diameter Pipe: An
Experimental and Numerical Proof of Concept for Automation and Manufacturing. Proceedings of the Institution of Mechanical Engineers,
Part B: Journal of Engineering Manufacture, July 15, 2010.
2. “Review The Common Defects In Friction Stir Welding”, Abdulaziz I. Albannai , INTERNATIONAL JOURNAL OF SCIENTIFIC &
TECHNOLOGY RESEARCH VOLUME 9, ISSUE 11, NOVEMBER 2020 , ISSN 2277-8616 .
3.. “Exit-hole repairing in friction stir welding of AA5456 pipe using consumable pin” by A.H. Ghavimi, M.R. Aboutalebi, and S.H. Seyedein
, Materials and Manufacturing Processes · June 2020, DOI: 10.1080/10426914.2020.1772491
4. Hattingh, D.G., von Welligh, L.G., Bernard, D., Susmel, L., Tovo, R., James, M.N., 2016. Semiautomatic friction stir welding of 38 mm
OD 6082-T6 aluminium tubes. J. Mater. Process. Technol. 238, 255–266. https://doi.org/10.1016/j.jmatprotec.2016.07.027.
5. Ismail A, The Preliminary Experimental Study of Friction Stir Welding on Aluminum Alloy 6063 Pipe Butt Joint, Marine Frontier,
MIMET TECHNICAL BULLETIN VOLUME 4 EDITION 1 2013.
6. Mike Page: "Friction stir welding broadens applications base" Archived 2008-11-22 at the Wayback Machine, Report of a EuroStir
meeting, 3 Sept 2003.
7. Meyghani, B., Awang, M. A Comparison Between the Flat and the Curved Friction Stir Welding (FSW) Thermomechanical
Behaviour. Arch Computat Methods Eng 27, 563–576 (2020). https://doi.org/10.1007/s11831-019-09319-x
REFERENCES

20. 8. METHOD AND APPARATUS FOR WELDING TWO WORK PIECES Gerhard Engelhard, Erlangen (DE); Rainer Bauer, Herzogenaurach (DE); Dieter
Pellkofer, Herzogenaurach (DE); Helmar Adams, Erlangen (DE) (73) Assignee: Framatome ANP GmbH, Erlangen(DE)
9. Scientific and Technical Reports Summary for WD-FH 0004 Task 1.3 GUIDELINES FOR FRICTION STIR WELDING by HOPE Center for Advanced
Technology.
10. Friction Stir Welding Technology: Adapting NASA's Retractable Pin Tool Purdue ECT Team Purdue University
11. S. W. Kallee, J. M. Kell, W. M. Thomas und C. S. Wiesner:"Development and implementation of innovative joining processes in the automotive industry",
Paper presented at DVS Annual Welding Conference "Große Schweißtechnische Tagung", Essen, Germany, 12–14 September 2005
12. NZ Khan, AN Siddiquee, ZA Khan, AK Mukhopadhyay, Mechanical and microstructural behavior of friction stir welded similar and dissimilar sheets of
AA2219 and AA7475 aluminium alloys, Journal of Alloys and Compounds 695 (2017) 2902-2908.
13. Bahemmat, Pouya & Haghpanahi, Mohammad & Besharati Givi, Mohammad Kazem & Reshad seighalani, Kambiz. (2012). Study on dissimilar friction stir
butt welding of AA7075-O and AA2024-T4 considering the manufacturing limitation. International Journal of Advanced Manufacturing Technology - INT J ADV
MANUF TECHNOL. 59. 10.1007/s00170-011-3547-4.
14. Friction Stir Welding Technology: Adapting NASA's Retractable Pin Tool Purdue ECT Team Purdue University
15. FRICTION STIR WELDING OF SPHERES, CYLINDERS, AND T-JOINTS: DESIGN, EXPERIMENT, MODELLING, AND ANALYSIS, by David H.
Lammlein ,Dissertation Submitted to the Faculty of the Graduate School of Vanderbilt University
16. Abdulaziz I. Albannai, Review The Common Defects In Friction Stir Welding, INTERNATIONAL JOURNAL OF SCIENTIFIC & TECHNOLOGY
RESEARCH VOLUME 9, ISSUE 11, NOVEMBER 2020 ISSN 2277-8616 .
17. Iqbal MP, Vishwakarma RK, Pal SK, Mandal P. Influence of plunge depth during friction stir welding of aluminum pipes. Proceedings of the Institution of
Mechanical Engineers, Part B: Journal of Engineering Manufacture. August 2020