View
11
Download
2
Category
Preview:
Citation preview
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
11
METHODOLOGY
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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)
Mechanical Engineering Department, IIT KHARAGPUR
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)
Mechanical Engineering Department, IIT KHARAGPUR
21
RESULTS & DISCUSSION
Mechanical Engineering Department, IIT KHARAGPUR
22
Surface temperature of Weld Nugget Zone
(a) = plunging & dwelling
(b) = Actual welding
(c) = Pulling the tool out
Mechanical Engineering Department, IIT KHARAGPUR
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)
Mechanical Engineering Department, IIT KHARAGPUR
24
Surface Appearance of Welded Samples
Flash at retreating side
Mechanical Engineering Department, IIT KHARAGPUR
� 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
Mechanical Engineering Department, IIT KHARAGPUR
26 Mechanical Engineering Department, IIT KHARAGPUR
Effect of Pin Profile & rpm
on Tensile Properties
27
Effect of Pin Profile & rpm on FSW Zone
900 rpm 1400 rpm 1800 rpm
Mechanical Engineering Department, IIT KHARAGPUR
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)
Mechanical Engineering Department, IIT KHARAGPUR
29
Effect of Weld Speed on Tensile Properties
Square pin tool
� As weld speed increases UTS decreases for
square pin profiled tool
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
31
Discussion
Square pin tool
20 mm/min
25 mm/min
Mechanical Engineering Department, IIT KHARAGPUR
32
Hardness Profile � Straight cylindrical � 1400 rpm & 16 mm/min � 50 gmf, 15 sec. � Microhardness varying
from 54-71 VH
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
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.
Mechanical Engineering Department, IIT KHARAGPUR
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.
Mechanical Engineering Department, IIT KHARAGPUR
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.
Mechanical Engineering Department, IIT KHARAGPUR
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
Mechanical Engineering Department, IIT KHARAGPUR
THANK YOUTHANK YOUTHANK YOUTHANK YOU
39 Mechanical Engineering Department, IIT KHARAGPUR
Recommended