Transcript New Developments in Advanced High Strenght Steels for

Advanced High Strength
Steels: an economical
solution for Automotive
Lightweight Structures
Advanced High Strength
Steels: inside an extended
steel grade offer for
Automotive
Automotive Steel Families
Family
Quality
AM offer
Eu Norm
Example of application
Drawing
DC01- DC07
ArcelorMittal 01-07
ArcelorMittal 51-57
EN10111
EN10130
EN10152
EN10327
Bodyside, roof, floor,
hood panels,
crossmembers
High Strength
steels
IFHSS
IF180 – IF300
BH
180BH – 300BH
Door, hood, decklid outer
panels
Members, crossmembers
Rephosphorized
H220 – H300
EN10268
EN10292
EN10152
EN10149
Isotropic
E220i – E260i
HSLA
CR HSLA 260 – 420
HR HSLA 320 -550
Advanced High
strength steels
Dual Phase
Complex Phase
TRIP
Martensitic
DP450 -1180
DP HY and HHE
TRIP 690 – 780
MS1200
EN10336
prEN10338
A, B, C Pillar R/F
Member R/F
Bumper, door beams
Rocker panel
Press hardened
steels
22MnB5
USIBOR
22MnB5
USIBOR1500AS
A Pillar, member, bumper
beam
Composite steels
Vibration damping
structural
Quietsteel
smoosteel
Dash panel, engine cover,
oil pan
Advanced High Strength
Steels: Massive and Growing
use in the Automotive
Industry
Advanced High Strength Steels
Estimated Market needs
• AHSS usage will grow
from 7% in 2006 to 11% in 2010,
mainly at HSS expenses
• A long term potential of
35% of AHSS in a BIW
has been estimated through a model
study
> 1 Mt in Europe
> 3 Mt in Europe
70%
Mass % in BiW
60%
50%
40%
7%
11%
38%
34%
35%
30%
20%
25%
10%
0%
2006
2010
2020
AHSS
HSS
Car Example
32%
Eu 4x4 – previous model AHSS
Eu 4x4 – new model
46%
AHSS
Source: Eurocarbody
Source EuroCarBody 2007
Advanced High Strength
Steels
WHY?
AHSS are dedicated to Structural parts
A-frame reinf.
Bumper Beam
Roof bow
B-pillar reinforcement
Front side members
Floor side reinf. - sill inner
Rear side member
WHY DOES THE NEED OF AHSS INCREASE ?
• Reduce CO2 emissions
• Reduce fuel consumption
• Safety requirements
• Equipment & Comfort
Car structure
mass
reduction
• Downgauging
• compensate by higher
crash performances of steel
• Cost effective
AHSS
Example in Brazil
Euroncap test as illustration
FRONTAL Crash regulation in 2010
=> would increase need of AHSS
Car crash situations
Situation where need is to control absorbed energy
Situation where need is to control intrusion (displacement)
AM test for: Energy absorption under
compressive load
Closed-Top-Hat
Sample
test conditions
Final specimen observation
Records
Energy Absorption
Average crushing force for 1.5mm thickness
1200 MPa
110
1000 MPa
Average force (kN)
100
89
800 MPa
90
700 MPa
80
600 MPa
70
500 MPa
60
57
50 52
50
63 64
73 75
71
69
79
101 103
92
83
40
40
30
4
50 500 600 590 500 690 780 800 800 980 980 000 HY 200
4
1
A
H DP DP DP
l
80 P1
IP
IP DP
IP MP DP
IP
L
P
r
e
1
c
r
lo lor
TR HS r TR lor
TR lor
TR r M P1
or
or
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rM
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l
l
Ar rce
r
r
r
r
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D
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l
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A Arc Arc Arc cel
el Arc cel
rc Arc cel rce
el
c
lo
rc
A
r
r
r
r
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r
A
A
A
A
A
A
c
A
Ar
0
or
0
26
• Increased energy absorption with higher UTS
• Ranking made at iso-part geometry
AM test for: Maximal Load under 3P bending.
test conditions: 3 point bending
45
Impactor
f 50
Maximum force
(ulitmate failure stress)
f 50
200
Support
700
100
140
Yield force
Displacement (mm)
75
30
records
Force (kN)
Sample
300
480
Impact speed: 8 m/s
Kinetic energy : 10 kJ
Final specimen observation
• Increased anti-intrusion with higher UTS
• Ranking made at iso-part geometry
Ar elo
ce r 0
4
Ar lor
ce H2
60
lo
r
Ar
D
ce P4
50
lo
r
Ar
D
ce P5
00
Ar lor
D
ce
P
lo
r T 600
Ar
R
ce
IP
lo
r H 59
Ar
0
ce SLA
lo
r T 500
R
Ar
ce IP6
90
Ar lor
D
ce
P
lo
r T 780
R
Ar
ce IP8
lo
00
r
M
Ar
ce P8
00
Ar lor
D
ce
P
lo
r T 980
Ar
ce RIP
lo
9
Ar
c e r M 80
lo
r D P10
0
Ar P11 0
Ar celo 80H
ce
rM
Y
lo
r U S1
2
si
bo 00
r1
50
0
Ar
c
Average force (kN)
max crushing force for 1.5mm thickness
70
60
1000 MPa
800 MPa
50
30
700 MPa
600 MPa
40
500 MPa
36 37
53
1500 MPa
1200 MPa 62
56 57
46 47 48
40 40 40 41
29 30 31
24
20
10
Strategic Interest in Advanced High
Strength Steels (AHSS) for Automotive
business is no more a question
Because it is the most economically
efficient solution to reach:
• Lightweighting goals in structural
areas of the car
• Safety goals in the safety-critical
parts
• Reduce complexity of stamped parts
Example of weight saving
potential
Example of Weight saving in Automotive parts: AM
generic steel solution catalogue for Bodyside
Reference : 5 doors European vehicle
“Bodyside” Scope
In the “solutions” catalogue: 1 very
efficient proposal for weight saving
A-PILLAR Upper INNER :
Trip 780 1.25mm
ROOF RAIL INNER :
DP980HY 0.7mm
A-PILLAR Upper R/F :
Usibor 0.9mm
A-PILLAR
Lower INNER
DP600 0.8mm
ROOF RAIL R/F
DP780 0.6mm
Reference
B-PILLAR TWB INNER :
DP980 HY 1.0 (up)
ARC04 0.7 (low)
B-PILLAR R/F TWB
Usibor 2mm (up)
Ductibor 1.6mm (low)
This solution
A-PILLAR R/F
Usibor 0.9mm
ROCKER INNER DP980HY 0.85mm
ROCKER R/F RR + ROCKER R/F FR : DP980 HY 0.85mm
Cost : +10%
Weight saving : -25%
What kind of steels are AHSS?
AHSS = MULTIPHASE STEELS
Strengthening by quenching generated hard
phases: martensite, bainite, retained austenite
Conventional = ferritic
Martensitic
DP
TRIP
1000 : 1 Le Pera
Ferrite Bainite
MP or CP
20 µm
AHSS = produced by conventional process
Run out table
Cooling and coiling
Continous casting
Slabs 25 t
Steelmaking
230 t
Cold rolling mill
Hot Rolling mill
Coils, 25t, length 1000 m
Hot Dip
Galvaninzing
line
Hot Dip galvaninzing
product
(coils, length 2000 m)
Metallurgy of
ArcelorMittal AHSS
MULTIPHASE structure  Manage phase transformation  Coupled key
factors: PROCESS and CHEMICAL COMPOSITION
PROCESS = control the structure at high temperature + the continuous cooling
strip temperature
« Conventional »
steels
TRIP steels
CGL or CAL
DP steels
time (s)
Adjusted by chemical
composition and
processing
Area of ferrite formation during cooling
Area of Bainite formation during cooling
Area of Martensite formation during cooling
ArcelorMittal WW
AHSS offer
FB
FB
DP DP
TRIP TRIP
XIP
DP
DP
FB
NAM
DP
FB
MP
FB
DP
FB
MP
DP
Mart
TRIP
PH
FB
EUR
PH
DP
DP
FB
DP
MP
FB
PH
SAM
MP
FB
DP
EUR: Europe
NAM: North America
SAM: South America
DP : Dual Phase (&CP)
MP: MultiPhase (CP)
Mart : Martensitic grade
PH: Press Hardening grade
FB : Ferrite bainite
TRIP : Transformation Induced Plasticity
Example of WW offer processus:
ArcelorMittal AHSS in Brazil
Concept and Know-How are transfered from original region (Eu, US) to
Brazil Plant with total technical support => OEM gets locally an
equivalent product compared to the original region
EUR & SAM
NAM Grade
Grade
UC
EG
T
450
DP500
T
500
490
EUR
NAM
DP590
T
600
590-600
EUR
NAM
DP780HFL
T
780HFL
DP590
T
600
590-600
EUR
NAM
EUR
DP590 HHE
T
600 HHE
590R
EUR NAM
EUR
DP690 HHE
T
DP780
T
780
DP780 HHE
T
780 HHE
DP780 LCE
T
780 LCE
FB450
T
450
FB540
T
540
FB560
T
560
FB590
T
590
FB590 HHE
T
590 HHE
MP800
T
800
Dual Phase
DP450
Ferrite-Bainite
Y/T
Multi-Phase
Generic
EUR
EUR
EUR
SAM
GI
GA
EUR
AS
ZA/AZ
EUR
NAM
EUR
NAM
NAM
NAM
EUR
NAM SAM
EUR
NAM
EUR
NAM SAM
EUR
NAM SAM
EUR
EUR
HFT690
NAM
NAM
780
NAM
NAM
780 LCE
540SF
EUR
EUR
EUR
EUR
SAM
NAM
EUR
SAM
EUR
EUR NAM
SAM
EUR
EUR
EUR NAM
590SF
SAM
EUR NAM
EUR NAM SAM
Commercial
Unexposed only
Commercial
Exp. and Unexp.
EUR
Customer Trials
HFL: High Fatigue Life, HHE: High Hole Expansion, LCE:Low Carbon Equivalent
Under
Development
Hot Rolled
Cold Rolled
Example of WW offer processus:
ArcelorMittal AHSS in Brazil
Example: Transfer DP600GI from Europe to Brazil (VEGA do Sul)
Typical value
ISO 20x80 LD
YS
MPa
UTS
MPa
T El
%
Europe
371
618
27
Brazil
382
611
26
ArcelorMittal keeps on
developing the AHSS family
Because:
• OEM needs are already growing for 1000MPa
and above grades.
• At these levels, Steelmaker and OEM must,
together, overcome increasing difficulties in part
forming, part welding and other in-use
properties.
CR DP 980
DP980 with excellent formability/bending
combination + good weldability
• Development in Europe and America with Low C/Low CEQ
of a new DP980 with low C content & improved drawability :
Toward low Ceq ~ 0.28-> ~ 0.23
Increase drawability : min 0.5t Bendability, +30% Hole Expansion, Robust Weldability
•
Excellent Combination of Properties:
–
–
–
• YS 650 MPa, TS 1020 MPa, TE 12-17% (Gauge dependent)
Qualified at Multiple Auto Manufacturers
Utilized in Vehicles beginning Model Year 2009
Applications include B-Pillars, Cross-members, Seat Parts
DP980LCE
DP980LCE
B-Pillar
Cross-members
MP800HY, a HR 800MPa steel
with good stretch flangeability
MP800HY, a HR 800MPa steel with good
stretch flangeability
M800HY
Ferrite + Granular bainite
MP800HY, a HR 800MPa steel with
good stretch flangeability
Sample
Thickness
mm
Direction
YS
MPa
TS
MPa
Uel
%
A%
JIS
3
LD
741
802
8.3
18.0
JIS
3
TD
807
829
6.6
16.6
JIS
2
LD
752
796
8.0
15.9
JIS
2
TD
796
821
6.9
15.0
MP800HY, a HR 800MPa steel with
good stretch flangeability
• Good bendability:
MP800HY
3mm

– Whatever the thickness is
– similar behaviour in rolling
and transverse direction
 without
crack

140°
initial = 10mm
• Conical hole expansion :
MP800HY
3mm
– Around 60% in average
– Development of 85% HE
HE at cracking
60%
=
45mm
Punch diameter : 75mm
• Dome stretching
underlines good formability.
MP800HY
3mm
Height without
crack
25mm
AHSS for roll-forming
ArcelorMittal AHSS Steels ≥1000
MPa for Roll Forming & bending
• DP 1180HY
– Mid-carbon steel
– YS ~950MPa, TS ~1200MPa, TE ~5% (ISO)
– Minimum bend radius of 2t
• Martensite 1100 / 1300 / 1500
– Lean alloying (C, 0.5Mn)
– YS ~1000/1150/1300MPa, TS ~1180/1380/1550MPa, TE >3%
– Minimum bend radius of 4t
• Industrial Applications include bumper beams, door
beams, rails in multiple vehicle platforms
Press-Hardened Steel:
USIBOR1500P® a special AHSS
Typical hot-stamping lines
Metallurgical structure after hot-stamping
USIBOR 1500P
100% martensitic
Hardness : 400 to 500 HV1
Homogeneous mechanical
properties in any point of the parts :
Ys  1100 MPa, Ts  1500 MPa, E (ISO)  6%
AlSi Coating after hot-stamping
Parts in Usibor 1500P
ArcelorMittal AHSS: Conclusion
• ArcelorMittal has in market an extended and Worldwide
Advanced High Strength Steels offer in order to
• Provide the most effective solution for car structure weight reduction
• where the OEM select and validate material to imagine new cars.
• where the OEM builds cars.
• ArcelorMittal keeps on developing new AHSS with
further improvements
• In lightweighting potential (higher Grades)
• In manufacturing properties
Thank you for you Attention