The Staybright™ revolution for automotive trims

The Staybright™ revolution
for automotive trims
Automotive Interiors Expo
June 2015
E. Lae, Constellium Technology Center
© Constellium P&ARP
Content
§  Constellium at a glance
§  C-TEC, Constellium Technology Center
§  Functional surfaces overview
§  The Revolution Staybright™
background
factors influencing alkaline resistance
experimental work
results
the Staybright™ concept
10,000 employees, €4.7 billion in sales*
23 manufacturing sites
Headquartered in Amsterdam, The Netherlands.
Corporate offices in Paris, France, Zurich, Switzerland and
New York, USA
Packaging and Automotive Rolled Products
§ 
§ 
§ 
§ 
€ 2.573* billion in revenues
#1 worldwide in closure stock
#2 in Europe for can body stock and #3 in North America
Major player in auto body sheet: #4 worldwide
* The combined unaudited pro forma revenue information for the year ended December 31, 2014 presented above gives
effect to the acquisition of Wise as if it had occurred on January 1, 2014. This information is presented for information
purposes only and does not purport to represent what Constellium actual revenues would have been had the acquisition
occurred on the date indicated, nor is it necessarily indicative of future results.
Constellium is a leader in innovative aluminium-based solutions
An introduction to Constellium 2015
3
C-TEC: a world-class technology center fully dedicated to innovation
223
Employees
93
Engineers
22 Unique
Nationalities
including
rapid prototyping
capabilities, simulation
tools and advanced joining
technologies such as
friction stir welding
58
PhDs
Over
150
patent families and trademarks
4
Functional surfaces: an overview of our current portfolio
Closures
Functional
Surfaces
Foilstock
Canstock
Foodstock
Heat
Exchangers
Auto
Body Sheet
#1
#1
#3
#1
#2
#3
#3
WORLD
Lighting
Solar
EUROPE
Cosmetics
Automotive
Decorative
5
Functional surfaces: automotive decorative
§ 
For high quality/decorative anodizing without etching
or high surface perfection
§ 
For chemical or electrolytic brightening followed by
anodizing for exceptional lustre requirements
§ 
For printing and lacquering
6
The Staybright™* revolution: background
§  Brightened and anodized aluminium alloys are extensively used for automotive exterior trims
§  No deterioration of the brightness and visual appearance of the trims is
expected during the whole lifetime of the vehicle
§  Particular concern is the development of automatic car wash detergent based on increasingly
alkaline chemistry
Upper roll formed and bent trim
Lower roll formed trim
Stamped window corner
trim
* Patent pending
7
Car trim manufacturing
§  Forming step
•  Stamping (window corner trim)
•  Roll forming (upper and lower trim)
§  Surface treatment step:
•  Brightening
•  Anodizing
§  Requirements for car trim sheets:
•  Mechanical properties
•  Formability
•  Surface quality
•  And increasingly… resistance to car wash test
8
Factors influencing alkaline resistance
1.  Surface treatment
There are some factors related to surface treatment that can improve alkaline resistance of bright
anodized aluminium:
•  Addition of silicates or transition metal to the sealing bath [1,2]
•  Different geometrical buildup of the oxide [3]
•  Addition of a silane based sol gel coating on the anodic layer [4]
2.  Metallurgical factors
However, market believes that some aluminium series have a better resistance than others.
Focus was put on metallurgical factors for the Staybright™ development
[1] S. Jolivet, Colmatage résistant aux milieux alcalins, Colloque sur Traitement de surface des alliages d’aluminium, CETIM/CERTEC, 2008
[2] Patent, Henkel, 2008(2006), Silicate treatment of sealed anodised aluminium
[3] R. Steins et al, SeALUmax – High Performance Anodized layers, European Aluminium Congress, 2009
[4] Patent, Erbslöh, 2009 (2007), Component made of Al alloy having very high corrosion resistance and method for the production thereof, WO2009068168
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Experimental: Car Wash test
Procedure drawn from automotive supplier technical specification which is representative of the typical
“car wash” test. It simulates within 10’ several hundred car washes.
Surface treatment
Representative of industrial surface treatment
Degreasing, etching, desmutting, electro brightening, anodizing, cold and hot sealing
Testing procedure
•  10 min immersion in solution pH 13.5
•  Rinsing in water and drying
•  Clean the sample with a polish cloth to remove
the corrosion byproducts
Assessment
•  No deterioration of brightness and visual appearance
•  Determination of weight loss
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Experimental: SEM characterizations
Field Emission Gun Scanning Electron Microscope (FEGSEM) observations were done
§  on car wash test samples to investigate attack mechanisms
§  on different alloys to characterize microstructure
Parameters tested:
§  Alloy:
5505: existing auto trim product
Al99.9MgSi (6401): benchmark extruded product
§  Temper:
hard temper or final annealed for 5505 alloys
aged (T6) or overaged for 6401 alloy
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Alkaline behavior of Al alloy in “pH13.5” solution
Anodic layer
chemical
dissolution
6µm
1.2mm
Metal substrate
10’ in car
wash test
solution
Localized
attacks
§  Homogeneous dissolution of the anodic layer, whatever the alloy and the temper
§  Localized attack through the whole thickness of the anodic layer in all samples at different levels,
depending on the alloy and temper.
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Influence of heat treatment, 5505 standard auto trim alloy
Good response to the car-wash test
5505 H19, hard temper
Bad response to the car-wash test
5505 H22, with final annealing
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Influence of heat-treatment, 6401 extruded alloy
Good response to the car-wash test
6401T6
Good response to the car-wash test
6401 overaged
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Comparison good/bad behavior
5505 H22
6401 T6
5505 H22
6401 T6
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Alloy and heat treatment influence
§  The difference of car wash test performances are mainly explained by differences in the intensity of the
localized attack.
§  The bad performance to car wash test is not intrinsic to the alloy 5505. It is linked to the final heat
treatment, hence to the process route.
§  SEM observations were run in order to understand the subtle differences linked to the heat treatment.
5505: Presence of fine Mg2Si particles (100-200nm)
in the annealed sample only.
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The Staybright™ concept
§  The final heat treatment applied to the 5505 alloy is detrimental to car wash test performance
§  This behaviour is due to a fine precipitation of Mg2Si particles, occurring during final heat treatment.
§  A specific process was developed to avoid Mg2Si precipitation.
§  It was tested successfully on a lab and industrial scale.
5505 H22: standard auto trim
Staybright™
Bad response to the car-wash test
Bad response to the car-wash test
Good response to the car-wash test
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OEM tests on Staybright™
§  Different materials were tested by our customer according to various OEM tests.
Alkaline Test
Material*
Serie (Standard material)
Staybright™
Benchmark product
extruded profile
pH12,5 - 10'
VW TL212
pH12,5 - 16'
Volvo
TR31816513
pH13,0 - 10'
Ford WSSM4P13-A
pH13,5 - 10'
VW TL182
Note 2
Note 4
Note 3
Note 5
Note 0,5
Note 0,5
Note 1,0
Note 4
Note 1
Note 1,5-2
Note 2-3
Note 4
*Surface treatment: bright anodizing process from our partner
§  The alkali resistance of the Staybright™ is today better than current industry benchmark
extruded profile.
§  The Staybright™ shows good alkali resistance up to pH13,0 according to Ford WSS M4P13-A.
Even at pH13,5 according to VW TL182 Staybright™ still shows acceptable results.
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OEM tests on Staybright™
The pictures of tested trims show clearly the good results:
pH12,5 - 10'
VW TL212
pH12,5 - 16'
Volvo TR31816513
pH13,0 - 10'
Ford WSS-M4P13-A
pH13,5 - 10'
VW TL182
Standard Material
Staybright™
Staybright™
Staybright™
Standard
Material
Staybright™
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Staybright™ market position
Product
Cost
Design
Alkaline
resistance
Standard 5505
$
Adapted for “quarterlight” thanks to roll
forming technology
No
Staybright
$$
Same as standard bright solution
Yes
5505 Top coated
$$$$$$$
Same as standard bright solution
Yes
Extruded
$$$
Limited to long non bent trims, cannot
work for “quarterlight”
Yes
The Staybright™ offers an optimal combination of cost, design potentialities and alkaline
resistance versus any other solution.
It was validated on OEM standard tests.
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THANK YOU FOR YOUR ATTENTION!
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