AUTOMOBILE STEEL WHEELS The Road to Dual Phase

AUTOMOBILE STEEL WHEELS
The Road to Dual Phase
Thomas Heck
Hayes Lemmerz International
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Automotive Wheels Have Been Manufactured
From Many Materials Through Out The
History Of The Automobile:
•
•
•
•
•
•
Wood
Steel (Casting, Sheet or Wire)
Aluminum (Casting, Forging, or Sheet)
Magnesium
Composites (FRP)
Combinations of the Above
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• From The Early Days Steel Has Been A
Predominant Choice For Wheel Materials:
Pressed Steel Wheel
Early Wire Wheel
Circa 1910
Circa 1920
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• The Age of Steel (1935 – 1980s): During This
Period Steel Wheels Dominated The Automobile.
By 1935 Wheel Diameters Had Decreased From
36” To 16” And Rim Widths Increased From 3”
to 6”. The Processes Of Stamping The Center
(Disc) And Rolling The Rim Were Well Suited
For High Volume Low Cost Production.
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Hot Rolled Low Carbon Steel Grades Were
Predominant For Wheels Prior To The 1970s And
Continue To Be Used Primarily on Rims Today:
• Discs:
• Rimmed 1012/1015 HRLC
• High Formability – Low Alloyed Outer Surface
• Converted to Continuous Cast 1012/1015 HRLC
• Rims:
• Mechanically Capped 1008/1010 HRLC
• Converted to Continuous Cast 1008/1010 HRLC
• Still the Predominant Steel Alloy for Rims
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• The Early To Mid 1970s Brought The Need To
Reduce Weight And Led To The Introduction Of
Higher Strength Steels Into Wheels:
• North America: 955X / 960Y HSLA Grades
• Precipitation Hardening w/Cb Additions for Grain Refinement
• Europe: Dual Phase Grades
• DP550 – Initially Si Chemistry
• Japan: SAPH 45 – 60 HSLA Grades
• C-Mn Grades with Improved Formability
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• This Demand For Higher Strength Steels Along
With A Need To Maintain Formability Led To The
1st Attempted Use Of Dual Phase Steel For Wheels
In North America:
• Mid 1970s – SAE980X Continuously Annealed Dual Phase
• Motor Wheel Corporation: AMC Wheel
• Kelsey Hayes: Cadillac Wheel
• Both Attempts Discontinued – Production Steel Problems
• Material Property Inconsistencies
• Surface Cosmetics due to High Si Levels
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• The 980X Experience Resulted In North
American Wheel Manufacturers And OEMs
Reluctant To Pursue Dual Phase Steel For
Wheels:
• Micro-Alloyed HSLAs became the Standard for
North American Light Weight Steel Wheel
Applications
• Dual Phase / Bainitic Steels became the Standard for
European Light Weight Steel Wheel Applications
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
2002 MY Steel Grade Usage - Automotive Wheels
100%
90%
80%
70%
60%
Bainitic(HR45-60)
Dual Phase
50%
HSLA
HRLC
40%
30%
20%
10%
0%
Rim Europe
Rim North
America
Disc Europe
Disc North
America
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Renewed Interest in Dual Phase:
• Aluminum Wheel Penetration
• Advantages of Styling and Weight
• Need for Improved Formability
• High Vent Wheel Development
• Renewed Need for Weight Reduction
• Dual Phase Development for Ford “Impact” Program
• Development of Cr Based DP Chemistry
• Increased Availability
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
Wheel Material Usage 1980 - Present
100.0%
90.0%
80.0%
70.0%
60.0%
50.0%
40.0%
30.0%
20.0%
10.0%
%Aluminum
%Steel
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2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
0.0%
AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• 1999: Hayes Lemmerz Began An Investigative
Study Into Utilizing Dual Phase In Steel
Wheels:
• Trial DP Steels from 7 Global Suppliers:
• 2 North American
• 1 South American
• 2 European
• 2 Asian
• Chemistry:
• Si (4 Suppliers)
• Cr (3 Suppliers)
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
O
Attributes Evaluated (Dual Phase vs HSLA):
O
Fatigue Strength
O Higher Base Tensile Strength
O 87 ksi min. vs 75 ksi min.
O Greater Work Hardening
O Paint Bake Hardening
O
Formability
O Lower Yield to Tensile Ratio
O 0.60 - 0.70 Typical vs 0.80 – 0.90
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
Average Rotary Fatigue Life Comparison
15x6 Drop Center Wheel
250000
200000
150000
100000
50000
0
Production Supplier #1 Supplier #2 Supplier #3 Supplier #4 Supplier #5 Supplier #6
060 HSLA Si=1.2%
Si=1.0%
Si=1.1%
Si=0.2%
Si=.02%
Si=1.1%
Dual Phase Supplier - Si Level
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
Average Rotary Fatigue Life Comparison
15x7 Full Face Wheel
800000
700000
600000
500000
400000
300000
200000
100000
0
Production - 060 HSLA
Supplier #4 - Si .02%
Supplier #5 - Si 1.1%
Dual Phase Supplier - Si Level
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
Wohler Curve Comparison – Dual Phase vs HSLA
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Evaluation Results: Benefits Confirmed
• Fatigue Performance Improvement
• Typically 50% or Greater Increase
• Allows for 10% Gauge/Mass Reduction
• Formability
• Reduced Forming Scrap
• Reduced Leuder (Strain) Lines
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Evaluation Results: Concerns
• Cosmetics
• “Tiger” (Silicon) Stripes
• Formability
• Higher Work Hardening (n-values)
• Redesigned Die Operations
• More Forming Up Front
• Consistency
• Heat to Heat Variation (1970’s Experience)
• Availability and Cost
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• Going Forward:
• 2006 MY Production Dual Phase Programs
• Flex Wheel Programs
• Cr Chemistry Dual Phase Specified
• 2 Suppliers Identified
• Additional Steel Suppliers to be Evaluated
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AUTOMOTIVE STEEL WHEELS
The Road to Dual Phase
• I’d Like to Acknowledge the Following Contributors:
• Steel Companies:
• USS / National Steel
• Kobe
• Usinor
• Usiminas
• Personnel
• Alan Coleman (Hayes Lemmerz)
• Mike Miller (Hayes Lemmerz)
• Hayes Lemmerz Sedalia, MO Plant
• Chuck Gregoire (National Steel)
• Weiping Sun (National Steel)
• Dave Ruhno (USS)
• Garth Lawrence (Smithers Scientific)
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DEVELOPMENT OF HIGH CHROME
DUAL PHASE FERRITE-MARTENSITE
STEEL FOR WHEELS APLICATION
João Alfredo Gritti
ArvinMeritor
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AUTO INDUSTRY DEMAND FOR
WHEELS IN THE LAST 7 YEARS
• Cost Reduction
• Weight Reduction
• Durability (+ fatigue)
• Appearance
• Better Uniformity
• Increase in Size
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ARVINMERITOR STEEL
APPLICATION
– Until 1986
• Mild Steel - Carbon/Manganese
Y. S. = 240 MPa Minimum (35 ksi)
T. S. = 350 MPa Minimum (50 ksi)
for disc and rim application
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ARVINMERITOR STEEL
APPLICATION
– End of the 1980’s
• High Strength Low Alloy - T. S. = 450 MPa (65 ksi) for disc
and rim application
(similar SAE J1392 050 YK)
• Hardening and grain size refining through precipitation of a
very fine carbonitrides in the ferritic matrix.
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ARVINMERITOR STEEL
APPLICATION
– 1992 / TWO POSSIBILITIES
•Continue to increase T. S. through the precipitation
hardening (Nb - Nb + Ti Microalloys).
Limitation: poor formability
•To develop the hardening by a phase transformation
produced by a controlled cooling at the hot rolled mill with
high formability.
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ARVINMERITOR STEEL
APPLICATION
– BAINITIC STEEL (SIMILAR SAE J1392 070XF)
•HSLA development - T. S. = 550 MPa (80 Ksi) for disc and rim
application
•Transformation hardening steel (Japanese Concept) 5% weight
reduction for disc application (compared to Nb Microalloyed)
•Improved formability, weldability and behavior at the hole
expansion test. Very good fatigue performance.
– Application: Toyota, DaimlerChrysler and Honda
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ARVINMERITOR STEEL
APPLICATION
– 1994 / DUAL PHASE STEEL DEVELOPMENT
•Hardening through a martensite phase produced by a
controlled cooling at the hot rolled mill, for disc application.
•Dual Phase is currently used by Japanese and Germany
Industries which reduced the disc weight 5 to 8 % (compared
to Bainitic Steel).
– Limitation: Maximum Thickness 4.5 mm
•Only for Disc Application
•Surface Quality (Red Scale)
•Simple Design Application
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DUAL PHASE STEEL
Microstructure
4% nital - 500x
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DUAL PHASE STEEL
Microstructure
Metabissulphite - 500 X
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DUAL PHASE STEEL
Chemical Composition
Material
(Wt %)
C
Mn
Si
P
S
Al
Cr
Ca
Dual Phase Steel
0,08
1,14 0,97 0,015 0,003 0,030 0,10 0,0014
Bainitic Steel
0,08
1,40 0,12 0,015 0,002 0,025
---
Nb Microalloy
0,10
0,55 0,02 0,016 0,008 0,045
---
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0,0014
---
Nb
--0,030
0,023
DUAL PHASE STEEL
Mechanical Properties
Typical Results
Material
YS
TS
(MPa)
(MPa)
YS/TS
El (%)
(GL: 50 mm)
Dual Phase Steel
390 (57 ksi) 650 (95 ksi)
0,60
26
Bainitic Steel
480 (69 ksi) 596 (86 ksi)
0,80
25
Nb Microalloy
390 (57 ksi) 488 (71 ksi)
0,79
31
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FATIGUE BEHAVIOR
DP STEEL WITH Si
USI-RW-600DP
Dual Phase Steel
B10%=105.310ciclos
USI-RW-550
Bainitic Steel
B10%=32.447 ciclos
USI-RW450
Nb Microalloy
B10%=23.229 ciclos
Thickness: 3.80 mm
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PRODUCT APPLICATION DAIMLER
CHRYSLER WHEEL
Wheel Design
Wheel 6 J x 15H2
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FATIGUE BEHAVIOR
DP STEEL AND Nb Microalloy
6 J x 15 CH WHEEL
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RED SCALE
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RED SCALE
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ARVINMERITOR STEEL
APPLICATION
– 1999 / DUAL PHASE HIGH CHROME
•Hardening through a martensite phase produced by a
controlled cooling at the hot rolled mill, for disc application.
– Material developed to eliminate red scale
– Limitation: Maximum Thickness 4.5 mm
•Only for Disc Application
•Simple Design Application
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ARVINMERITOR STEEL
APPLICATION
Chemical Composition
Material
(Wt %)
C
Mn
Si
P
S
Al
Cr
Ca
N
Dual Phase Si
0,08
1,14 0,97 0,015 0,003 0,030 0,10 0,0014
0,0047
Dual Phase Cr
0,07
1,20 0,03 0,060 0,002 0,025 0,58 0,0023
0,0054
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ARVINMERITOR STEEL
APPLICATION
Mechanical Properties
Typical Results
Material
YS
TS
(MPa)
(MPa)
YS/TS
El (%)
(GL: 50 mm)
Dual Phase Si
390 (57 ksi) 650 (95 ksi)
0,60
26
Dual Phase Cr
402 (59 ksi) 637 (93 ksi)
0,63
25
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FATIGUE BEHAVIOR DPSTEEL
THICKNESS 3.80mm
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ARVINMERITOR STEEL
APPLICATION
Application of HSLA material provides the following
possibilities in terms of weigh reduction.
RIM
Nb Microalloy
Bainitic Steel
10%
DISC
Nb Microalloy
Bainitic Steel
5 to 8%
Bainitic Steel
DP with Cr
5 to 8%
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ARVINMERITOR STEEL
APPLICATION
45
Q1 Meritor Grade
C - Mn - Steel
Elongation (%)
40
Q4 Meritor Grade
Nb Microalloy
35
30
Q8 Meritor Grade
Dual Phase Steel
Q7 Meritor Grade
Bainitic Steel
25
20
350
400
450
500
550
600
Tensile Strength (MPa)
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650
700
THANK YOU!
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w w w . a u t o s t e e l . o r g
Sponsored by: American Iron and Steel Institute
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