This document introduces a new aluminium alloy called Surfalex® HF that is designed for demanding automotive body parts. Surfalex® HF offers improved formability over existing alloys, allowing for more complex part designs and sharper character lines without compromising other key properties. Experimental testing and simulations validate that Surfalex® HF exhibits higher work hardening at high strains, enabling an estimated 10-15% better formability. Surfalex® HF maintains the same strength, surface quality, corrosion resistance, and hemming performance as existing alloys. The new alloy allows automakers to further reduce vehicle weight through more extensive use of aluminium in body panels.

1. Pushing the limits of formability:
A new aluminium outer skin
sheet product for most
demanding car body parts
Dr. Sabine Philippe, Dr. Petar Ratchev
Bad Nauheim, May 11, 2016

2. Agenda
1. Constellium
2. Drivers and strategy for skin alloy development
3. A new aluminium outer skin sheet product
2A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

3. Agenda
1. Constellium
2. Drivers and strategy for skin alloy development
3. A new aluminium outer skin sheet product
3A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

4. An introduction to Constellium 2015
Constellium is a leader in innovative aluminium-based
solutions
Over 10,000 full-time employees
€5.2 billion in sales
22 manufacturing sites
C-TEC, our world-class Technology Center
Headquartered in Amsterdam, The Netherlands.
Corporate offices in Paris, France, Zurich, Switzerland and
New York, USA
2015 key figures
411.05.2016A new aluminium outer skin sheet product for most demanding car body parts

5. Second largest-volume, fully
integrated rolling mill in Europe
World-class recycling center
Integrated hot/cold-rolling line
Joint venture with UACJ (Japan),
majority owned by Constellium
NEUF-BRISACH, F SINGEN, D
Bowling Green, KY, US
(under construction)
Expanding our automotive body sheet capacity
5A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

6. Our auto body sheet portfolio with increasing
performance
6
Strongalex®
Ultralex®
Securalex®
Securalex® HS
Surfalex®
Surfalex® HS
Surfalex® HF
Formalex®Plus
Strength/Mech.
Resistance Crash Design & Style
Surface
Aspect
PRODUCT PERFORMANCE
For replacement of high
strength steel parts
and further down gauging
For parts which
need energy
absorption
For all
visible parts
For parts with
complex design
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

7. Agenda
1. Constellium
2. Drivers and strategy for skin alloy development
3. A new aluminium outer skin sheet product
7A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

8. Challenges for skin alloy development
surface quality :
orange peel,
roping defects
hemming
corrosion
resistance
in-service strength
(dent resistance)
deep drawing, stretch
forming
sharp lines
In-service performance Ability to form the part
Improving formability, while maintaining a high level of in-service properties
8A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016
edge-cracking

9. Edge-cracking improvement
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 9
Optimized hole geometry:
Significant improvement by
increasing local curvatures
in critical areas
Material optimization:
Higher elongations lead to higher crack resistance
0
0,1
0,2
0,3
0,4
0,5
5182 6016
HoleExpansionRatio
HER=(Df-D0)/Df
die-cut laser-cutCutting quality:
Significant influence of the cutting
process and parameters
Laser cutting results in higher max.
edge strain than press trimming
process
old hole
geometry
new hole
geometry

10. Formability improvement
Material optimization:
Higher FLC0 to delay cracks
Higher work hardening at high
strains
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 10
Reduced friction:
To allow material to flow and more
homogeneously distributed deformation
Design optimization:
The height to radius ratio is
important when designing for
aluminium
28
32
36
40
44
0,060,080,10,120,140,16
depthat1stcrack(mm)
friction coefficient
oil-based drylube
ester-based drylube
red = previous design
blue = modified design to solve formability issues

11. Current design requires sharp character lines
Sharp character line on the part = small external radius (internal tool radius + ~sheet
thickness)
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 11
Material optimization:
Higher work hardening at high strains
Stretch-bending tests
We test the alloy ability to form sharp lines on
laboratory scale using stretch-bending
Optical measurement of the outer radius

12. Development strategy of new aluminium skin alloys
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 12
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,00 0,10 0,20 0,30
n-value
true strain
current alloy targeted alloy
We use numerical simulation to define the
material needs for real parts. From virtual
alloys that allows a given part to be formed
we have developed the chemical
composition and process route to achieve
mechanical properties
Several traditional target material
properties (n5, r10, ∆r, A80, etc) are
insufficient indicators of the ability to form
real, complex part in 6xxx-series
aluminium alloys
Key development target for us is enhanced
work hardening at high strains

13. Agenda
1. Constellium
2. Drivers and strategy for skin alloy development
3. A new aluminium outer skin sheet product
13A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

14. New aluminium skin alloy: Surfalex® HF
Surfalex® HF gives an improved formability of 10-15% vs. incumbent skin alloys,
without compromising any other requirement of outer skins
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 14
In-service strength
(dent resistance)
Corrosion
resistance
Roping
Orange peel
Stretch forming &
Stretch bending (sharp lines)
Deep drawing
Hemming
Hole expansion
Ability to form the partIn-service performance
Surfalex®
Surfalex® HF
conventional 6016

15. New aluminium skin alloy: Surfalex® HF
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 15
* 2% + 20’@185°C
Si Fe Cu Mn Mg Cr Zn TiSi Fe Cu Mn Mg Cr Zn Ti
1,0 – 1,5 <0,50 <0,20 <0,20 0,25 – 0,60 <0,10 <0,20 <0,15
Ag% A80%
Surfalex® 22 25
Surfalex® HF 26 29
16
18
20
22
24
26
28
30
elongation(%)
Typical average of Ag and A80 Typical in-service* strength
Rp0.2
Surfalex® 210
Surfalex® HF 210
50
70
90
110
130
150
170
190
210
230
in-servicestrength(MPa)
Composition range within AA6016:
Significant increase of elongations while maintaining the same in-service strength:

16. 0,18
0,2
0,22
0,24
0,26
0,28
0,3
0,32
0,34
-0,2 -0,1 0 0,1 0,2 0,3 0,4
majorstrain
minor strain
Surfalex
SurfalexHF
Optimized for forming of complex parts
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 16
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0 0,05 0,1 0,15 0,2 0,25
nvalue
true strain
Surfalex
SurfalexHF
Higher strain hardening at high strains,
for improved stamping and better ability to
form sharp “character” lines
Forming limit curve is improved,
particularly in plane strain, enabling the
forming of complex and deep parts

17. 17
Improved formability validated experimentally …
The LDH (Limiting Dome Height) test aims to reproduce press conditions in a simple,
fast laboratory procedure
This test shows good correlation with plane-strain industrial failures
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016
120 mm
160 mm
0° or 90°
24
25
26
27
28
29
30
Surfalex® Surfalex®HF
Limitingdomeheight
=heightatfailure(mm)
0°
90°
hemispherical punch + lock beads
sample dimensions

18. 18
Improved formability validated experimentally…Surfalex®
Surfalex®HF
Constellium in-house stamping trials using difficult door inner tooling
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

19. 19
… and numericallySurfalex®
Surfalex®HF
Surfalex® HF gives clear formability improvement both in simulation and in prototype
stamping trials of difficult parts
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016

20. 2
3
4
5
6
7
10 15 20 25 30
outerradii(mm)
punch displacement (mm)
Surfalex® -r=1
Surfalex®HF -r=1
Surfalex® -r=2
Surfalex®HF -r=2
Surfalex®
/r=1
“Sharper” lines can be achieved
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 20
In this stretch-bending test, a high punch displacement is the key indicator of the ability to
form sharp lines. The given outer radii values depend on the tool geometry & setup.
Lower outer radii can be obtained with Surfalex® HF
Interrupted stretch-bending tests
at different punch displacements
(up to failure) & optical
measurement
Surfalex®
HF /r=1
Surfalex®
HF /r=2
Surfalex®
/r=2Max. punch displacement before
failure is indicated by an arrow
/r=1
/r=1
/r=2
/r=2

21. Additional relevant forming properties
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 21
Surfalex® HF also shows a lower in-plane anisotropy, that means a more similar forming
behavior in the 3 directions, and good hemming aptitude
► r-value
153 155
0
20
40
60
80
100
120
140
160
180
Surfalex Surfalex HF
bendingangle(°)
► bending angle:
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Surfalex Surfalex HF
r-value(8-12%)
0° 45° 90°

22. Perfect surface aspect and corrosion resistance
complying with skin products
A new aluminium outer skin sheet product for most demanding car body parts 11.05.2016 22
NOK OK
Trend towards thinner paints mean less tolerance for surface disturbance and/or roping
lines after forming: excellent surface quality of Surfalex® HF
Good corrosion resistance: IGC results within specifications
IGC:
4
roping:
Surfalex® HF
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 100 200 300 400 500
Cumulativedistributionof25
measurements
Depth of attacks (µm)
Surfalex®
Surfalex®HF

23. Summary
Key trend for skin alloy developments = very few design
compromises when converting from steel to aluminium.
High formability is required (more complex and deep parts,
sharp lines, …)
Key forming parameter is strain hardening at high strains
We now offer a new skin outer alloy: Surfalex® HF with
significant improvements vs incumbent Al alloys
improved stamping of complex parts, including bodyside
panels
better ability to form sharp “character” lines
and with no compromise in
in-service strength
hemming performance
surface aspect quality

24. Auto
moti
ve
Circl
e
Inter
nati
onal09/05/201624
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