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International IIW Conference Welding & Materials – CROATIA 2007 Friction Stir Welding of Automotive Aluminium Alloys CENTRO DE ENGENHARIA MECÂNICA DA UNIVERSIDADE DE COIMBRA CEMUC A Loureiro 1 , RM Leal 2,1 , C Leitão 1 , DM Rodrigues 1 , P Vilaça 3 1 CEMUC, Department of Mechanical Engineering, University of Coimbra, Coimbra, Portugal 2 ESAD.CR, Politecnical Institute of Leiria, Caldas da Rainha, Portugal 3 DEM-IST, Technical University of Lisbon, Portugal
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Page 1: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Friction Stir Welding of Automotive

Aluminium Alloys

CENTRO DE ENGENHARIA MECÂNICA DA UNIVERSIDADE DE COI MBRA

CEMUC

A Loureiro 1, RM Leal2,1, C Leitão1, DM Rodrigues1, P Vilaça3

1 CEMUC, Department of Mechanical Engineering, University of Coimbra, Coimbra, Portugal

2 ESAD.CR, Politecnical Institute of Leiria, Caldas da Rainha, Portugal

3 DEM-IST, Technical University of Lisbon, Portugal

Page 2: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

I Introduction

II Experimental Procedure

III Results and Discussion

Weld appearance

Microstructure

Hardness Analysis

Tensile properties

IV Conclusions

� OUTLOOKCEMUC

Page 3: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� Introduction

Nowadays reality

• Worldwide Market• Demanding Customers• Saturated Markets• Competitors Aggressiveness

Actions to develop

• Reduce production time/costs• Improve production flexibility • Increase quality• Weight reduction

Main objective

Improve Competitiveness

Promising solution

Friction Stir Welding

CEMUC

Page 4: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Friction stir welding (FSW) process gives several benefits in welding difficult to weld aluminium alloys and allows joining dissimilar materials. Despite the evolution of the process in recent years, several difficulties continue constraining its generalization in industry:

� Limited knowledge in design of the welding tools;

� A strict control of the welding parameters is needed, chiefly in welding of very thin sheets ;

� The reduction in mechanical properties in welds in some aluminium alloys.

The aim of this investigation is to study the effect of friction stir welding parameters on the microstructure and mechanical properties

of welds in thin sheets (1 mm thick) of two automotive aluminiumalloys

CEMUC� Introduction

Page 5: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Materials:

� Aluminium alloy AA 5182-H111(provided by Novelis Switzerland SA )

� Aluminium alloy AA 6016-T4 (provided by Novelis Switzerland SA )

CEMUC� Experimental procedure

Alloy Si Fe Cu Mn Mg Cr Zn Ti AA 5182-H111 0.2

max. 0.35 max.

0.15 max.

0.2 – 0.5

4.0 – 5.0

0.1 max.

0.25 max.

0.1 max.

AA 6016-T4 1.0 – 1.5

0.5 max.

0.2 max.

0.2 max.

0.25 – 0.6

0.1 max.

0.2 max.

0.15 max.

Chemical composition (wt. %)

Alloy Rp0.2 (MPa) Rm (MPa) A50 (%) AA 5182-H111 114 275 24 AA 6016-T4 115 226 24

Mechanical properties

Page 6: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Process parameters:

CEMUC� Experimental procedure

Series rotation speed ω (rpm)

travel speed v (mm/min)

Tool angle α (º)

Plunge depth (mm)

Rotation to travel speed ratio (ω/ v)?

1rst 1800 160 2.5 0.95 11.25 2nd 1120 320 0 0.95 3.5

Tools

Welding parameters

1rst series 2nd series

Page 7: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� Results and Discussion

Weld appearance and cross section

CEMUC

AA 5182-H111

AA 6016-T41rst series

AA 5182-H111

AA 6016-T42nd

series

Page 8: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� Results and Discussion

Distribution of precipitates in welds of first series in AA 6016-T4 alloy

CEMUC

Advancing side Retreating side

Plate thickness

Polished weld surface

Page 9: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� Results and Discussion

Microstructure of parent materials and nugget of welds

CEMUC

AA 5182-H111 AA 6016-T4

Nugget

250 µm 100 µm

100 µm 100 µm

Parent material

Page 10: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� Hardness Analysis

Hardness variation in welds in AA 5182-H111

CEMUC

40

50

60

70

80

90

-15 -10 -5 0 5 10 15 20 25

Distance (mm)

Har

dnes

s H

V0,

05

5182-H111

55S1-M5

55S2.1-M1

TMAZ HAZHAZ

HAZHAZ TMAZ

Advancing Retreating

Page 11: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Hardness variation in welds in AA 6016-T4

CEMUC� Hardness Analysis

30

35

40

45

50

55

60

65

70

75

80

-15 -10 -5 0 5 10 15 20 25

Distance (mm)

Har

dnes

s H

V 0

.1

B6S1-M2

66S1-M5

66S2.2-M1

HAZHAZ TMAZ

Advancing Retreating

Page 12: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Tensile properties of welds in AA 5182-H111

CEMUC� Tensile properties

0

50

100

150

200

250

300

0 0.05 0.1 0.15 0.2 0.25 0.3

εεεε

σσσσ [M

Pa]

55S2 5BM 55S1

Page 13: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Tensile properties of welds in AA 6016-T4

CEMUC� Tensile properties

0

50

100

150

200

250

0 0,05 0,1 0,15 0,2 0,25 0,3

εεεε

σσσσ [M

Pa]

6BM 66S1 66S2

Page 14: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

Comparative analysis of tensile properties of welds

CEMUC� Tensile properties

Weld ref.

Rp0.2

(MPa) Rm

(MPa) A50 (%)

ηRp0.2 ηRm Fracture localization

55S1 113 268 18 0.99 0.97 HAZ 55S2 117 282 23 1 1 BM 66S1 109 200 15 0.95 0.89 TMAZ/HAZ 66S2 116 185 9 1 0.82 TMAZ

Page 15: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

� ConclusionsCEMUC

� The tool with scrolled shoulder allowed reducing the tool tilt angle to zero and the prominence in the advancing side of the welds;

� This tool geometry allowed also to diminish the plate thicknessreduction in the welds;

� The decrease in heat-input refined the microstructure of the nugget and increased the hardness of the thermo-mechanically affected zone of welds in alloy AA5182-H111, without reducing joint efficiency ;

� On the contrary the welds of the second series in alloy AA 6016-T4 showed a reduction in hardness and joint efficiency.

Page 16: Friction Stir Welding of Automotive Aluminium Alloys - UC · Friction Stir Welding of Automotive Aluminium Alloys ... (provided by Novelis Switzerland SA ) ... Friction Stir Welding

International IIW Conference Welding & Materials – C ROATIA 2007

CEMUC

Friction Stir Welding of Automotive

Aluminium Alloys

CENTRO DE ENGENHARIA MECÂNICA DA UNIVERSIDADE DE COI MBRA

A Loureiro 1, RM Leal2,1, C Leitão1, DM Rodrigues1, P Vilaça3

1 CEMUC, Department of Mechanical Engineering, University of Coimbra, Coimbra, Portugal

2 ESAD.CR, Politecnical Institute of Leiria, Caldas da Rainha, Portugal

3 DEM-IST, Technical University of Lisbon, Portugal