Potential for Mn in New Automotive Steels

Hot Rolled Products Overview and Evolution

Elongation(%)

40

35

30

25

20

15

10

400 500 600 700 800 900 1000

USIPHASE D550USIPHASE D 600

USIFORM 450-550

USIDUR315-420

USIPHASE D800

USIFORM 600

Trend

USIPHASE T 800

Increase Strength-Ductility Balance Availability of very HSS in low thicknesses

Precoated Products

1100 T.S. Mpa

USIPHASE M 1000 (t 1.6 mm)

TrendUSIPHASE M 800 (t 1.6 mm)

USIDUR 700

Trend to low thicknesses

TS (

MP

a)

El ( %)20 30 4010 50

300

400

500

600

700

800

TRIPDual PhaseDual Phase HSSMicroalloyed (HSLA)HS IsotropicBake-Hardening (HS BH)IF HSRephosphorized USISTAMP06USISTAMP07

Colled rolled steels1000

900

Floor Panel in EDDQ Steel

Seat Stand

USIPHASE D 600Ferrite + Martensite

20 µm

Dual Phase Microstructure

USIPHASE T 800Ferrite + Bainite + Residual Austenite

TRIP Microstructure

20 µm

Arcelor Offer: Ts 600MPa

10

15

20

25

30

35

0 1 2 3 4 5Available thicknesses (mm)

Tota

l elo

ngat

ion

B/ HDG(<4mm)Usiform 600

Usiphase D60

B/ EZ(<3mm)

Usiphase D600

B/HDG/EZ

Arcelor Offer: Ts 800MPa

10

15

20

25

30

35

0 1 2 3 4 5Available thicknesses (mm)

Tota

l elo

ngat

ion

B/ EZ(<3mm) /HDG(<3mm)

Usiphase M800

Usiphase D80

B/ EZ(<3mm)

Usiphase D750

B/HDG/ EZ(<2mm)

Usiphase T800

B/EZ

Usiphase T800

B/EZ

Arcelor Offer: Ts 1000MPa

Available thicknesses (mm)

5

10

15

20

25

30

0 1 2 3 4 5

B/ EZ

Usiphase T1000

B/ HDG

Usiphase D1000B(<2mm) /HDG

Usiphase M1000Tota

l elo

ngat

ion

Chassis Parts

Dimensioning Stresses Processing Constraints

StiffnessE

Crash(YS, TS,El%, n)

Fatigue(TS)

ExceptionalStresses(YS, E)

Profilage Welding Stamping Stretchflanging

Wheel Rims

Wheel disks

Suspension arms

Engine cradles

Rear Axle

* * * * * * *

*

*

*

*

*

*

*

*

*

*

* * *

* * *

* * *

* * *

* * *

* * * * * *

* * *

* * *

Nakazima-Hecker Method

Hole Expansion Ratio'(AC%=(D-Do)/Do x100))

T.S. (MPa)

400 500 600 700 800 900 1000

180

160

140

120

100

80

USIDUR315-550

USIFORM 450-550

DP55 - 60

USIFORM 600

USIFORM 800

Die

Punch

Load 400N(rubber punch

diameter 15 mmhardness =80 shore)

1

2 3

4

0,60

0,80

1,00

1,20

1,40

1,60

1,80

2,00

POINT 1 POINT 2 POINT 3 POINT 4

Rem

aine

d de

form

atio

n (m

m)

USIPLUS180 0,67 mm

USIPHOR220 0,68 mm

USISTAMP04 0,78 mm

DENT RESISTANCE

INTEREST OFBAKE-HARDENING

STEEL GRADESUSIPLUS

Bake HardeningBake Hardening : 170: 170°°C / 20mnC / 20mn

-- No No ageing and low ageing and low BH BH withoutwithout predeformationpredeformation-- HighHigh BH BH afterafter predeformation predeformation

BH and Ageing Behaviour of DP and TRIP Steels

BH and Ageing Behaviour of DP and TRIP Steels

AgingAging : 70: 70°°C / 10HC / 10H

020406080

100

0 2 4 6 8 10% predeformation

BH after Tensile TestAgeing after T.T.BH after SkPAgeing après SkP

020406080

100

0 2 4 6 8 10 12 14Predeformation (%)

DP450DP500DP600DP750TRIP800

MPaMPa MPaMPa

Crash Energy Management

Anti Intrusion

Energy Absorption

Weight reduction potential in flexion vs. USISTAMP 04 (%)

0%10% 9%

20% 19%23% 24%

32% 34%

58%

33%37%

49% 47%

0,00%

10,00%

20,00%

30,00%

40,00%

50,00%

60,00%

Usistam

p04Usip

hor280

Usidraw

440

Usidur31

5Usip

haseD

450

Usiphas

eD50

0Usip

haseD

600

HLE500

Usiphas

eT80

0Usib

or 1500

Usiphas

eD75

0

Usiphas

eM80

0

Usiphas

eM10

00

Usiphas

eTR10

00

Ultimate force

Lightening potential in axial compression with respect to Usistamp04 (%)

32,430,8

15,1

28,7

31,2

27,928,8

21,0

24,4

19,8

16,0 15,3

10,4

8,09,4

7,1

0,00,0

5,0

10,0

15,0

20,0

25,0

30,0

35,0

Usipha

seTR10

00Usip

hase

D800

HM12HM12

stam

pUsip

hase

M1000

Usipha

seM80

0

Usipha

seTR80

0stam

pUsip

hase

TR800

Usipha

seD75

0HLE

500

Usipha

seD60

0Usip

hase

D500

Usipha

seD45

0Usid

raw44

0Usid

ur315

Usipho

r280

Usistam

p04

DP and TRIP typical mechanical properties

DP and TRIP typical mechanical properties

0100200300400500600700800900

0 5 10 15 20 25 30 35 40Elongation %

Con

vent

iona

l Str

ess

(MPa

)

Dir. Yp0,2 El(%) Ag(%) rd r delta r nd nT 519 840 26,3 21,0 1,18 1,01 0,07 0,217 0,221L 478 830 28,3 22,5 0,90 0,228D 508 834 25,5 21,1 0,97 0,221

0100200300400500600700800900

10001100

0 0,05 0,1 0,15 0,2 0,25Rational Strain

Rat

iona

l Str

ess

(MPa

)

TRIP800TRIP800

Usiphor280Usiphor280

DP600DP600DP750DP750

Usistamp Usistamp 0404

Usidur360Usidur360

TRIP800TRIP800

DP600DP600DP750DP750

Usistamp Usistamp 0404

Usidur360Usidur360

TS

Influence of 10% prestrain on Usiphase D600 GA Fatigue Resistance

Alternating Tension Rs = 0,1

Mechanical CharacteristicsYS = 379 MPa ; TS = 630 MPat = 1,95 mm

Fatigue Results

State σd 5.106 cyclesDelivery 455 MPaPrestrain 10% 541 MPa 300

350

400

450

500

550

600

100000 1000000 10000000

Number of cycles

10% Prestrain

As delivered

Max Stress (Mpa)

0

1

2

3

4

5

6

7

300 400 500 600 700 800

TS (MPa)

Sprin

gbac

kA

ngle

°Problems to considerProblems to consider

SpringbackSpringback ControlControl OthersOthers-- avoid wrinklesavoid wrinklesformation formation then difficuthen difficuto to eliminateeliminate-- Stamping Stamping Presses Presses Capacity Capacity -- tools coatingstools coatings-- toolstools pollution by pollution by steel coatingssteel coatingsdue to due to heatheat-- welding adjustmentswelding adjustments

Decrease with- die radius- punch-die clearance- blankholder force increase

--j/j/epep.=1.2 .=1.2 -- R 3R 3-- R 2R 2

--j/j/epep.=1 .=1 -- R 3R 3-- R 2R 2

--j/j/epep.=0.95 .=0.95 -- R 3R 3-- R 2R 2

UTS (MPa)

A ( %)10 20 30 40 50

300

400

500

600

700

800

1000

900

60 70 80

UTS (MPa)

A ( %)10 20 30 40 5020 30 40 50

300

400

500

600

700

800

1000

900

60 70 8060 70 80

VHS FeMn steels

very ductile FeMn

Development(product & process)

Explorationof metallurgies

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

Cold rolled grades

UTS (MPa)

A ( %)10 20 30 40 50

300

400

500

600

700

800

1000

900

60 70 80

UTS (MPa)

A ( %)10 20 30 40 5020 30 40 50

300

400

500

600

700

800

1000

900

60 70 8060 70 80

VHS FeMn steels

very ductile FeMn

Development(product & process)

Explorationof metallurgies

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

Cold rolled grades

Arcelor FeMn – TWIP programme target & status

UTS (MPa)

A ( %)10 20 30 40 50

300

400

500

600

700

800

1000

900

60 70 80

UTS (MPa)

A ( %)10 20 30 40 5020 30 40 50

300

400

500

600

700

800

1000

900

60 70 8060 70 80

VHS FeMn steels

very ductile FeMn

Development(product & process)

Explorationof metallurgies

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

Cold rolled grades

UTS (MPa)

A ( %)10 20 30 40 50

300

400

500

600

700

800

1000

900

60 70 80

UTS (MPa)

A ( %)10 20 30 40 5020 30 40 50

300

400

500

600

700

800

1000

900

60 70 8060 70 80

VHS FeMn steels

very ductile FeMn

Development(product & process)

Explorationof metallurgies

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

FeMn (targets)TRIPDual phaseHSLAIFHSBHRephosphorisedMild

Cold rolled grades

Arcelor FeMn – TWIP programme target & status

First stage : heating in furnaceFirst stage : heating in furnace

HeatingHeating55--10 min10 min

880880--950 950 °°CCAustenitisationAustenitisation

alloying reaction alloying reaction on coatingon coating

TYPICAL HOT-STAMPING (« direct process»)

Hot stamping : what is it ?

Second stage : hot forming Second stage : hot forming (600(600--800800°°C)C) and ...and ...

HeatingHeating55--10 min10 min

880880--950 950 °°CCAustenitisationAustenitisation

alloying reaction alloying reaction on coatingon coating

Tools : 20°C < T <200°C

First stage : heating in furnaceFirst stage : heating in furnace

TYPICAL HOT-STAMPING (« direct process»)

Hot stamping : what is it ?

ThirdThird stage : quenchingstage : quenching between the between the diesdies

Tools : 20°C < T <200°C

First stage : heating in furnaceFirst stage : heating in furnaceSecond stage : hot forming and ...Second stage : hot forming and ...

TYPICAL HOT-STAMPING (« direct process»)

HOT STAMPING (« direct process »)Fast transfer time between furnace and diesFast transfer time between furnace and dies

Stamping with high speed and low pressureStamping with high speed and low pressuress (200 to 500 (200 to 500 T)T)

Stamping is carried Stamping is carried out out between between 800800°°C C and and 600600°°CC

0

100

200

300

400

500

600

700

0.00 0.10 0.20 0.30 0.40 0.50 0.60

Ger

çek

Ger

ilme

(MPa

)

At high temperature, USIBOR 1500 P has

very high elongations (> 50%)

20°C

400°C

600°C

800°C

Destacking before ovenentrance

Temperature ~ 900°C,Austenitization of blanks

Rapid transfer from ovento the die set

Simultaneous formingand quenchingDies are water cooledPart temperature afterforming: ~ 80°C

TYPICAL HOT-STAMPING LINE (« direct process »)

Bumper Bumper beambeam

Side rail memberSide rail member

BB--pillar reinforcementpillar reinforcement

Door beamsDoor beams

Hood reinforcementHood reinforcementAA--pillar reinforcementpillar reinforcement

USIBOR 1500 P APPLICATIONS

Renault Laguna II

FRONT BUMPER BEAM OF THE LAGUNA IIFRONT BUMPER BEAM OF THE LAGUNA IIUSIBOR 1500 PRECOATED IN 2 mm THICKNESSUSIBOR 1500 PRECOATED IN 2 mm THICKNESS

(PHOTO WITH THE KIND PERMISSION OF RENAULT SA)(PHOTO WITH THE KIND PERMISSION OF RENAULT SA)

USIBOR 1500 P

Citroën C5

SOFEDIT SOFEDIT PicturesPictures

Hot blank justHot blank justbefore stampingbefore stamping

Stamped blankStamped blankbefore cuttingbefore cutting

A PILLAR RENFORCEMENT OF THE CITROA PILLAR RENFORCEMENT OF THE CITROËËN C5N C5USIBOR 1500 PRECOATED IN 1.17 mm THICKNESSUSIBOR 1500 PRECOATED IN 1.17 mm THICKNESS

(PHOTO WITH THE KIND PERMISSION OF PSA PEUGEOT CITRO(PHOTO WITH THE KIND PERMISSION OF PSA PEUGEOT CITROËËN)N)

USIBOR 1500 P

WELDED BLANKS MARKET IN EUROPE

020406080

100120140160

Millions blanks

1997 1999 2001 2003 2005 2007

EUROPE

EUROPE

Multi Thickness Blanks

MTB are Steel Solutions which allow :

• Weight Saving• Reduction of the number of parts• Reduction of the manufacturing time for the function• Reduction of functionnal cost on the Global chain

And / Or an increase of in-service performance.

TYPICAL INDUSTRIAL APPLICATIONS

–Closure inners(hinges and latch reinforcements)–Shock tower–Reinforcements of pillars, – side rails, – front and rear rails and transverse members–Local reinforcements of floor panel–...

CASE OF A DOOR INNER

Door Inner2,3 Kg of weight reduction

•Suppresssion of the post-assembly hinges

•Reinforcement integrated

•Better stiffness

•Cost reduction

•Weight reduction

Laser Tailored Blank

Patchwork

TWB contribute to mass of vehicle reduction

Body side : 8 kg of weight saving (25%)

B. Pillar2.5 kg of Weight Saving

(14%)Suspension support:

1,2 Kg of weight saving (33%)

Rail2,4 Kg of weight saving (18,5%)

Door Inner2,3 Kg of weight saving (17%)