presentation1 · • mechanical testing – hardness results – tensile test results – forming...
TRANSCRIPT
Friction Stir Welding of AA 6016-T4 thin sheets
DM Rodrigues1, A Loureiro1, C Leitao1, RM Leal2,1, P. Vilaça3
1CEMUC, Department of Mechanical Engineering, University of Coimbra, Portugal2ESAD.CR, Polytechnic Institute of Leiria, Caldas da Rainha, Portugal
3 IST, Technical University of Lisbon, Lisbon, Portugal
61st Annual Assembly and International Conference of theInternational Institute of Welding
Graz, Austria, 6 - 11 July 2008
IIW 2008
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Outline
• Introduction
• Base Material
• Welding Procedure
• Microstructural analysis of the welds
• Mechanical testing
– Hardness results– Tensile Test results– Forming Results
• Conclusions
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Introduction
• AA 6061
• AA 6082
• AA 6063
• AA 6056
• AA 6022
• AA 6005
• AA 6013
• Artificially aged temper condition (T5, T6 and T651)
• Plates thicker than 3 mm
Friction Stir Welding of AA 6016-T4 thin sheets
Influence of process parameters
Previous works:
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Base Material
• AA 6016 aluminium alloy • 1.0 mm thick rolled plates• heat-treated and naturally aged
• good hemming properties• good weldability• very good corrosion resistance• very good formability • no stretcher strain marks
< 0.15< 0.2 < 0.1 0.25–0.6< 0.2 < 0.2 < 0.5 1.0–1.5AA 6016-T4
TiZnCrMgMnCuFeSiAlloy
1 µm
Nominal chemical composition of the AA 6016 alloy (wt-%)
Mean grain size: 23 µµµµm
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Welding Procedure
0º1120 rpm320 mm/minTool 2
Scrolled Shoulder
2.5º1800 rpm180 mm/minTool 1
Conical shoulder
Tool tilt angleRotation speed (ωωωω)Welding speed (v)
Conical shoulder Scrolled ShoulderShoulder:8º inclination cavity10 mm in diameter Pin:cylindrical threaded3 mm in diameter1 mm long
Shoulder:helical flutes14 mm in diameter Pin:cylindrical threaded3 mm in diameter0.85 mm long
Hot Welds
Cold Welds
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Macrostructural analysis of the welds
Hot Welds Cold Welds
Thickness undermatch No thickness undermatch
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Microstructural analysis of the welds
Hot Weld
Cold Weld
AA 5182-H111 AA 6016-T4
AA 5182-H111 AA 6016-T4
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Microstructural analysis of the welds
Hot Weld Cold Weld
2.2 µm 2.2 µm
Mean grain size: 7 µµµµm
Mean grain size: 2 µµµµm
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Hardness Profile
50
55
60
65
70
75
80
85
90
-10 -5 0 5 10
Distance from weld center line (mm)
Har
dnes
s (H
V 0
.1)
Hot WeldCold Weld
Advancing Side Retreating Side
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50
55
60
65
70
75
80
85
90
-10 -5 0 5 10
Cold Weld
Advancing Side Retreating Side
Hardness Profile
Cold Weld
1
1
2
2
3
3
4
4
2,2 µm
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Tensile test results
50
70
90
110
130
150
170
190
210
230
0 0.05 0.1 0.15 0.2 0.25
Engineering Strain
Eng
inee
ring
Str
ess
(MP
a)
AA 6016-T4
Cold Weld
Hot Weld
AA 6016-T4
Cold Weld
Hot Weld
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0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70
Punch Displacement (mm)
Pun
ch F
orce
(kN
)
Hot Weld
Cold Weld
AA6016-T4
Formability results
punch speed - 100 mm/minclamping force - 8kN
200 mm
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Formability results
Hot Weld
wrinkling
Cold Weld
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Conclusions
• Defect free welds were obtained for both tool geometries and welding parameters
• Hot welds were in evenmatch relative to the base material
• Cold welds were in undermatch relative to the base material
• Both welds had lower ductility than the base material• Cold welding improved the formability of the TWB