Friction Stir Welding Avindra Thube Prsenttn

Influence of FSW Parameters & Tool Pin Profile

On Formation of FSW Zone & Tensile Properties

In 5083 Aluminum Alloy

Presentation By,

Ravindra Thube (10ME61R17),

Under the guidance of,

Dr. Surjya K. Pal,

Department of Mechanical Engineering ,

Indian Institute of Technology Kharagpur.

� Background

� Literature Review

� Methodology

� Results and discussion

� Conclusions

Contents

2 Mechanical Engineering Department, IIT KHARAGPUR

3

BACKGROUND

Mechanical Engineering Department, IIT KHARAGPUR

4

� Aluminum: Due to light weight & high

strength to weight ratio the consumption has increased in automobile, shipbuilding & aerospace industries

� The unique combination of light weight and relatively high strength makes

aluminum the second most popular metal that is used in industry

Typical Applications of Aluminum Alloy

http://www.dlr.de/wf/en/desktopdefault.aspx/tabid-2132/2294_read-3738/

5

5xxx Series Aluminum Alloys (AA 5083)

� 5xxx alloys are strengthened with magnesium addition from 4- 5.5 %

� Non Heat treatable & work hardened alloy

� Excellent toughness, weldability and corrosion resistance even at salt

water

� Representative alloys: 5052, 5083 and 5754

� Typical ultimate tensile strength range: 125 to 350 MPa

Text book of ‘Friction Stir welding & Processing’ by: R.S.Mishra & M.W. Mahoney

� Defects like porosity, slag inclusion, solidification cracks etc. which

deteriorate the weld quality

� Melting of the material causes loss of alloying elements

� Distortion of workpiece

� Environmentally hazardous, requires shielding gas

� Requires additional process

� Difficulties in welding of AA5083 by conventional welding

6

Friction Stir Welding

(b) (a))

(c) (d)

(a) Principle of FSW [13] (b) Showing AS & RS [14] (c) Keyhole [12] (d) Actual FSW [15]

7

Advantages of FSW Over Fusion Welding

� Retain near-parent metal properties across the weld

� Join similar and dissimilar materials

� The weld quality is excellent

� Because no melting of materials it avoids the weaknesses caused by

distortion and metallurgical reactions

� No consumables (filler material, shielding gases)

� Improved safety absence of toxic fumes & absence of spatter of

molten material

� Easily automated on simple milling machines


8

Author

Year Contribution

Peel et al. 2003 Found that the weld properties were dominated by the

thermal input rather than mechanical deformation by the

tool for AA5083, 3 mm plate thickness.

Fujii et al. 2005 Studied the effect of tool shape on mechanical properties

and microstructure and found that for 5083-0, 5mm plate

thickness whose deformation resistance is relatively high,

weldability is significantly affected by the rotation speed.

Hirata et al. 2006 Found that the hardness of stir zone increased with

decrease in friction heat flow because the grain size in stir

zone decrease with friction heat flow for AA5083.

Elangovan et al. 2007 Studied the influence of tool pin profile and welding speed

on formation of FSW zone in AA2219 aluminum alloy of

6 mm plate thickness and found that square pin profiled

tool produces mechanically sound welds.

Literature Review


9

Author

Year Contribution

Han et al. 2009 Weld fracture were observed at the stir zone and optimum

FSW conditions are weld speed of 124 mm/min and

rotational speed of 800 rpm.

Rajkumar et al.

2010 Studied the influence of FSW process and tool parameters

on strength properties of AA7075-T6 of 5 mm plate

thickness and found that joint fabricated at 1400 rpm, 60

mm/min weld speed, 8kN axial force, 15 mm shoulder

diameter, 5 mm pin diameter showed higher strength

properties with threaded tool.

Kumar et al. 2011 Results show that tool rotational speed, welding speed and

tool shoulder diameter are most significant parameters

affecting axial force and heat input.

Leitao et al. 2012 Studied the high temperature plastic behaviour and its

relation with weldability in FSW for AA5083 & AA6082.

Literature Review


10

� Formation of FSW joints by using five different tools (taper cylindrical, triangular, straight cylindrical, square and cone) and different process parameters for 2.5 mm plate thickness of AA5083 aluminium alloy

� Study the effect of tool pin profiles and welding parameters

on the formation of � Friction stir weld zone � Tensile properties � Hardness profile

Following are the objectives of the present work :

Objectives


11

METHODOLOGY


12

Sheet Material � AA5083 aluminum alloy � Plate thickness 2.5 mm

Material Selection for FSW

Chemical Composition (wt%)

AA5083 [16]

Fe 0.4

Si 0.4

Mn 0.4 - 0.1

Mg 4.0 – 4.9

Zn 0.25

Ti 0.15

Cr 0.05- 0.25 XRD

Tensile yield strength 125 MPa

Ultimate tensile strength 175 MPa

Elongation (%) 6.668

Vickers microhardness 75 HV

Melting temperature 639 °C


13

� Stainless steel 316 (SS 316)

Tool Design and Tool Material

Chemical Composition (wt%) of SS 316 [16]

Mn 2.00

Si 1.00

S 0.030

P 0.045

Cr 16-18

Ni 10-14

Iron Remaining

Shoulder diameter (D) = 15 mm

Pin length (L) = 2 mm

(b) Tool Design (a) Square


14

Tool Pin Profiles

Taper cylindrical

Triangular Square Straight cylindrical

Cone

Swept vol. 39.269 39.269 39.269 39.269 39.269

Area in static cond.

Area in dynamic cond.

(a) Taper cylindrical

(b) Triangular (c) Square (d) Straight cylindrical

(e) Cone


15

Experiments

Process parameters Values

Rotational speed (rpm) 900, 1400, 1800

Welding speed (mm/min) 16

D/d ratio of tool 3.75

Pin length (mm) 2

Tool shoulder diameter, D (mm) 15

Pin diameter, d (mm) 5

Plunge depth (mm) 0.1 mm

� No of tools = 5

� No. of rotational speeds = 3

� No. of welding speed = 1

� Total weld = 5 x 3 = 15


16

Measurement of Power Input

(e) LabVIEW Display (d) Data Acquisition Card

(a) Power Supply

(b) Power Sensor

(c) FSW Machine

� Power data recording

frequency is 1 sample

per second

� Output in KW

� Power consumption w.r.t.

time was measured

(f) Power Sensor


17

Measurement of Temperature

(c) LabVIEW Display (b) Data Acquisition Card

(a) FSW Machine

� Temperature data recording

frequency is 1 sample per

second

� Output in millivolts (1 mv= 1 0C)

� Temperature w.r.t. time were

measured

(d) Handheld infrared thermometer mounted over tripod


FSW Setup

(e) HIT

(f) LabVIEW Display (d) Data Acquisition Card

(a) Power Supply

(b) Power Sensor

(c) FSW Machine

19

�Standard specimens (a) –

To evaluate the tensile properties of the base metals

and welded joints

�The standard tensile properties:

0.2% yield strength (YS), ultimate

tensile strength (UTS),%

elongation, % joint efficiency,

fracture location

� Strain rate = 2 mm/min

Uniaxial Tensile Testing

INSTRON Uniaxial Tensile

Testing Machine

(a)


20

(a) Macrostructure analysis

� Inspecting cross-sectional weld quality

(b) Microhardness measurements

� Vickers micro hardness testing- hardness

variation of the metals in the friction stir weld

zone (FSW), thermo mechanically affected

zone (TMAZ), heat affected zones(HAZ)

and the base metals

� 50 gmf ; 15s dwell time

Metallographic Observations

Vickers micro hardness

testing apparatus

Etched sample

LEICA stereo zoom microscope with

Qwin-V3 display

(a)

(b)


21

RESULTS & DISCUSSION


22

Surface temperature of Weld Nugget Zone

(a) = plunging & dwelling

(b) = Actual welding

(c) = Pulling the tool out


a

23

Discussions 1) As rpm increases power

consumption increases

irrespective of tool pin profile

2) % increase in power

consumption is more from 900

to 1400 than 1400 to 1800 rpm

Power Input

(a) = plunging & dwelling

(b) = Actual welding

(c) = Pulling the tool out

(a) (c) (b)


24

Surface Appearance of Welded Samples

Flash at retreating side


� Flash defect occurs at retreating side for all four pin profile tools at 1800 rpm except straight cylindrical pin profile tool

25

Fracture locations in tensile tested welded specimens

(a)

(b)

Effect of Pin Profile & rpm on Tensile Properties



Effect of Pin Profile & rpm

on Tensile Properties

27

Effect of Pin Profile & rpm on FSW Zone

900 rpm 1400 rpm 1800 rpm


28

Effect of Weld Speed on Tensile

Properties

Rotational speed 1400 rpm

Welding speed

(mm/min)

16, 20, 25 & 31.5

No. of joints

formed

8 (2 x 4)


29

Effect of Weld Speed on Tensile Properties

Square pin tool

� As weld speed increases UTS decreases for

square pin profiled tool


16 mm/min

25 mm/min

20 mm/min

31.5 mm/min

30

Square pin tool Straight cylindrical

16 mm/min

20 mm/min

25 mm/min

31.5 mm/min

FSW Zone


31

Discussion

Square pin tool

20 mm/min

25 mm/min


32

Hardness Profile � Straight cylindrical � 1400 rpm & 16 mm/min � 50 gmf, 15 sec. � Microhardness varying

from 54-71 VH


0

10

20

30

40

50

60

70

80

-12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12

Hardness (HV)

Lateral distance from weld line (mm)

33

� For AA5083 whose deformation resistance is relatively high, tool

pin profiled designs had little effect on heat input and power

consumption but considerable effect is observed on tensile

properties

� As rotational speed increases surface temperature of nugget zone

and power consumption increases but % increase in both form 900

to 1400 rpm is more than % increase from 1400 to 1800 rpm

irrespective of tool pin profiled

� Joints fabricated at rotational speed of 1400 rpm and weld speed of

16 mm/min exhibited superior tensile strength properties and

produces defect free FSW zone irrespective of tool pin profile

except triangular pin tool

Conclusions


34

� Weldability is significantly affected by the rotational speed. At high

1800 rpm straight cylindrical tool is the best; at rotational speed 1400

rpm straight cylindrical and square tool are the best; while for 900

rpm triangular and square tool are the best

� Maximum strength properties of 105 MPa yield strength, 149 MPa of

tensile strength and 84.9 % of joint efficiency respectively was

attained without any defect for the joint fabricated using straight

cylindrical tool at rotational speed of 1400 rpm and weld speed of 16

mm/min

Conclusions


35

Acknowledgements

I acknowledge my sincere thanks to my project guide, Dr. Surjya K. Pal,

for his kind permission to pursue project work under his supervision and

the technical staff at the Department of Metallurgical & Materials

Engineering, Central Research Facility (CRF), Steel Technology Centre

(STC),Central Workshop & Instruments Service Section (CWISS) for their

unalloyed co-operation while working in their various laboratories and

workshops.


36

References

[1] European Aluminum Association, Aluminum in Commercial Vehicles, Brussels Rev.1. April 2011. Chapter II Aluminum in Transport, p.7-13, Chapter V Typical Alloys for Commercial Vehicles, 2011. p. 44–9. [2] G. Raynaud, P. Gomiero, The Potential of 5383 Alloy in Marine Applications. Proceedings of Alumitech‘97 - Transportation, Sponsored by Aluminum Association, Inc., May 20-23, Atlanta; 1997; 1997. p. 353–66. [3] A. Duran, R. Dif, New Alloy Development at Pechiney: a New Generation of 5383. In: Wilson PA, Hearn GE, editors. Conf. Proc. FAST 2001, vol. 3. Southampton: Southampton University; 2001. p. 223–30. [4] C. Leitao, R. Louro, D. Rodrigues, Analysis of high temperature plastic behaviour and its relation with weldability in friction stir welding for aluminium alloys AA5083-H111 and AA6082-T6’, Journals of Materials and Design 37 (2012) 402–409. [5] C. Zhou, X. Yang, G. Luan, Fatigue properties of friction stir welds in Al 5083 alloy, Scripta Materialia 53 (2005) 1187–1191. [6] H. Fujii, L. Cui, M. Maeda, K. Nogi, Effect of tool shape on mechanical properties and microstructure of friction stir welded aluminum alloys, Materials Science and Engineering A 419 (2006) 25–31.


37

References

[7] H. Lombard, D. Hattingh , A. Steuwer, M. James, Optimising FSW process parameters to minimise defects and maximise fatigue life in 5083-H321 aluminium alloy, Engineering Fracture Mechanics 75 (2008) 341–354. [8] R. Kumar, K. Singh, S. Pandey, Process forces and heat input as function of process parameters in AA5083 friction stir welds, Trans. Nonferrous Met. Soc. China 22(2012) 288298. [9] M. Han, S. Lee, J. Park, S. Ko, Y. Woo, S. Kim; Optimum condition by mechanical characteristic evaluation in friction stir welding for 5083-O Al alloy, Trans. Nonferrous Met. Soc. China 19(2009) s17-s22. [10] S. Rajakumar, C. Muralidharan, V. Balasubramanian; Influence of friction stir welding process and tool parameters on strength properties of AA7075-T6 aluminium alloy joints, Materials and Design 32 (2011) 535–549. [11] K. Elangovana, V. Balasubramanianb; Influences of tool pin profile and welding speed on the formation of friction stir processing zone in AA2219 aluminium alloy, Journal of materials processing technology 200 (2008) 163–175. [12] R. Mishra, Z. Ma, Friction stir welding and processing, Materials Science and Engineering: R: Reports, Volume 50, Issues 1-2, 31 August 2005, Pages 1-78.


38

References

[13] http://www.thefabricator.com/article/forengineers/an-introduction-to-friction-stir-welding

[14] http://www.alcotec.com/us/en/education/knowledge/qa/What-is-friction-stir- welding-of-

aluminum.cfm

[15] http://www.dlr.de/wf/en/desktopdefault.aspx/tabid-2132/2294_read-3738/

[16] http://www.referansmetal.com


THANK YOUTHANK YOUTHANK YOUTHANK YOU


Documents

Friction Stir Welding Avindra Thube Prsenttn