Heat Treatment Processes

Institut Jean Lamour, UMR 7198 CNRS - Université de Lorraine Parc de Saurupt, 54011 Nancy Cedex France

Sabine DENIS

ANF Métallurgie fondamentale 22-25 oct 2012, Aussois

SOLIDIFICATION

FORMING

HEAT TREATMENT

WELDING CUTTING ...

LIQUID METAL PROCESSING

Microstructures Mechanical properties

Problem of heat treatment of metallic alloys

Etude Sogerail, Irsid, LSG2M, Cemef Study Sogerail, Irsid, LSG2M, Cemef

Heat treatment of metallic alloys

Control of microstructures

desired mechanical properties

Control of thermal gradients

avoid/limit deformations

avoid/limit residual stresses (quenching) or obtain desired residual stress distributions

(surface heat treatments, thermochemical treatments)

Better optimization = modelling and numerical simulation

Development of internal stresses during cooling

qualitative approach (Rose et Bühler 1968)

Origin of internal stresses : Heterogeneous deformations

- thermal - phase transformations

Origin of residual stresses and deformations :

Heterogeneous deformations -  plastic

- phase transformations

Example of experimental residual stress profiles Water quenching of a 60NiCrMo11 steel cylinder (diameter 40mm, length 120mm)

Sachs method X ray diffraction

1 r/R

RX

Sachs

PhD Josserand 1980

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

Process heating, cooling

1972 …prediction of thermal stresses (Al alloys, Ti alloys) ≈ 1980… main advances including phase transformations in steels ≈ 2000… precipitation Al alloys - consideration of fluid flow (gaz quenching)

DEFORMATION X

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

Process : heating, cooling

Overview of necessary experimental knowledge, present models, some open questions and example of results in steels

DEFORMATION

Modelling of phase transformation kinetics (for the purpose of predicting internal stresses and deformations) • Global models (JMAK): (1980 -1995) - Modelling anisothermal kinetics from CCT diagrams - Modelling kinetics from IT diagrams (additivity principle)

PHASE RC : prediction of kinetics during heating and cooling in steels from isothermal kinetics (additivity principle) HEATING IT diagram austenitization kinetics carbon content of austenite and grain size

yk = ymaxk (1 - exp (- bk tnk))

COOLING : IT diagram

austenite proeutectoïd constituent pearlite, bainite . incubation period : Scheil’s method S = finc Σ Δti /τi τi = f(T, grain size, comp., stress) . progress n, b = f (T, grain size, comp., stress)

austénite martensite : ym = yγ [1 – exp (-α (Ms – T))]

Ms = f (grain size, comp., stress) Hardness: HV = Σi,k dykHVk HVk= f(Tformation, comp.)

PhD Fernandes, Farias, Mey…

Example : Gaz quenching of carburized cylinders

Cylinders diameter 16mm length 48mm steel 27MnCr5 Austenitization 930°C 40min Gaz quenching (nitrogen 4 bars)

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8distance sous la surface (mm)

taux

de

carb

one

(%)

0

200

400

600

800

1000

0 100 200 300 400 500 600 700

surfacecentre

tem

péra

ture

(°C

)

temps (s)

Temperature evolutions (median plane)

Radial carbon profile

Dissertation C. Aubry 1998

0

20

40

60

80

100

3 102

4 102

5 102

6 102

7 102

8 102

9 102

0 0,2 0,4 0,6 0,8 1

austéniteferritebainitemartensitetaux normé d'autorevenu

dureté

frac

tion

volu

miq

ue (%

)

dureté (HV

)

distance sous la surface (mm)

0 100 200 300 400 500

austéniteferritebainitemartensitetaux normé d'autorevenu

0

20

40

60

80

100

temps (s)

frac

tion

volu

miq

ue (

%)

0

20

40

60

80

100

0 100 200 300 400 500 600

austénitemartensitetaux normé d'autorevenu

frac

tion

volu

miq

ue (

%)

temps (s)

Final microstructure and hardness distributions

Kinetics of transformation

surface centre

14

0 1 2 3 4 5 60

0.2

0.4

0.6

0.8

1

Austénite.Perlite.Ferrite.Martensite.

Temps (s).

Frac

tion

volu

miq

ue.

80

200

400

600

800

1000

1200

0 1 2 3 4 5 6 7

0.0.5651.0651.542

Tem

péra

ture

(°C

).

Temps (s).

Profondeur (mm):

Traitement Pt=960W. V=4.5mm/s.

FRAC

TION

VOL

UMIQ

UEPROFONDEUR (mm).

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5

1

Austénite résiduelle.

Martensite homogène.

Mart. riche en carbone. Mart. pauvre en

carbone.

Ferrite.

Perlite.

2345

Pt=960W. V=4.5mm/s

Dissertation Boufoussi 1993

Ex. Prediction of microstructures during laser hardening of steels Plate moving under laser beam – steel C42 Source laser Pt.

Zone affectéeDéplacement de la pièce. V.

Gaz de protection

OptiqueDistributionénergétique

15

Dure

té.

Profondeur (mm).

0

200

400

600

800

1000

0 0.5 1 1.5

Calcul.Exp. Hv 0.3

0

200

400

600

800

1000

0 1 2 3 4 5

CalculExp. Hv 0.3.

Dure

té.

Largeur (mm).

Hardness and microstructure distributions comparison calculation-experiment

width HAZ : exp. 8,4mm calculation 8,5mm

depth HAZ: exp. 0,85mm calculation 1,06mm

Modelling of phase transformation kinetics (for the purpose of predicting internal stresses and deformations) • Global models (JMAK): most commonly used for steels - Modelling anisothermal kinetics from CCT diagrams - Modelling kinetics from IT diagrams (additivity principle)

can predict volume fractions of the phases for complex situations limitations : no morphological parameters of the microstructures

difficult to take into account prior plastic deformation effects • Nucleation, growth, coarsening models - precipitation in Al alloys D. Godard 1999 - tempering of martensite in steels Y. Wang 2006

volume fractions of the precipitates, size distributions matrix chemical composition

Multicomponent alloys - concommittant precipitations - thermodynamic equilibrium : . solubility product (stochiometric compositions) or coupling with THERMOCALC - nucleation rate homogeneous/heterogeneous nucleation, take account of elastic strain energy - growth (dissolution) coarsening rates diffusion controlled local equilibrium at interfaces Gibbs Thomson effect and effect of elastic strain energy

Results volume fractions of the precipitates size distributions matrix chemical composition

Modelling of phase transformation kinetics : nucleation, growth, coarsening

during the treatments isothermal and anisothermal

0

0,2

0,4

0,6

0,8

1

0 100 200 300 400 500 600 700

carbure !, cal.cémentite cal.

carbure !, exp.cémentite, exp.

Température (°C)

0

0,05

0,1

0,15

0

100

200

300

400

500

600

0 20 40 60 80 100

Carbure !Cémentite

Température

Temps (s)

0

0,005

0,01

0,015

0,02

0,025

0,03

0,035

0,04

1 10 100 1000 104 105

C, Cal.Cr, Cal.Mn,Cal.Cr, Exp.Mn,Exp.

Composition (atomique)

Temps (s)

0

2 10-9

4 10-9

6 10-9

8 10-9

1 10-8

0

100

200

300

400

500

600

0 20 40 60 80 100

Rayon critique, Cal.Rayon moyen Cal.

Température

Temps (s) 0

2 10-8

4 10-8

6 10-8

8 10-8

1 10-7

1 10 100 1000 104 105

Rayon critique, Cal.Rayon moyen, Cal.Rayon Exp.

Temps (s)

Cementite

ε carbides (Fe2,4C) coherent, homogeneous nucleation, cementite (Fe,M)3C) incoherent, heterogeneous nucleation (disloc.)

PhD Y. Wang 2006

Modelling of precipitation during tempering of martensite in steels

steel 80MnCr5 heating : 10°C/s holding at 500°C

100nm

100nm 600°C 2h

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

DEFORMATION

Température

Température de transformation

Austénitization

Transformation bainitique

Temps Contrainte

0

200

400

600

800

1000

1200

0 200 400 600 800 1000 1200 1400

TempératureContrainte

DéformationTem

péra

ture

(°C

) / c

ontra

inte

(M

Pa)

Temps (s)

εpt

Transformation plasticity Acceleration of the transformation

Bainitic transformation under stress (thermomechanical simulator DITHEM)

Steel 35MnV7 Transformation at 350°C

PhD M Veaux 2003

0

2

4

6

8

10

0 0,5 1 1,5 2 2,5 3

350°C450°C

Plas

ticité

de

trans

form

atio

n (%

)

Contrainte normalisée

____ 10 µm

bainite formed at 350°C under 310MPa

Mechanisms of transformation plasticity - plastic accommodation of tranformation strains - orientation of transformation product

Transformation deformation versus applied stress

Variations of times corresponding to 10% and 90%of length variation

Acceleration of the transformation : increase of nucleation rate and modification of growth rate

Phenomenological modelling of the coupling between internal stress states and transformation kinetics

During heat treatment material is under triaxial stress states, small plastic deformations

For diffusion dependent transformations effect of plastic strain and pressure can be assumed negligible acceleration of the transformation due to stress Dσ = Δt/t0 = h(σe) σeVon Mises stress h experimental function Incubation period : τσ = τ (1+Dσ) (Scheil’s method) Progress of transformation : nkσ = nk bkσ =bk/(1+Dσ)nk (JMKA law)

For martensitic transformation Effect of plastic strain assumed negligible in comparison with stress effect Variation of Ms with stress state ΔMs = Aσm + B σe A and B constants (Inoue)

Dσ

-150

-100

-50

0

50

100

150

0 50 100 150 200 250 300 350

Con

train

te (M

Pa)

Temps (s)

-200

-150

-100

-50

0

50

100

0 50 100 150 200 250 300 350

Con

train

te (M

Pa)

Temps (s)

Ex effect of internal stress – kinetics interaction

Temperature evolutions (center and surface)

Calculated axial stress versus time at the surface Axial stress versus time in the center

Oil quenching of cylinders diameter 35mm length 105mm steel 35MnV7 (PhD M Veaux 2003)

bainite

bainite

Ms Ms

Complex stress evolutions due to temperature gradients

Ex. effect of the internal stress-kinetics interaction

350

400

450

500

550

-15 -10 -5 0 5 10 15

Dur

eté

(Hv)

Rayon (mm)

in the center Hardness profiles

with interaction

Comparison with experiment

-  important effect in a massive specimen -  prediction not fully satisfactory need of better knowledge of the effect of complex thermomechanical paths

without

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

DEFORMATION

Calculation of stress and strain fields Hyp. small deformations, material homogeneous isotropic Stress equilibrium Compatibility of deformations Behavior law of the material

Effect of phase transformations - change of mechanical properties - additionnal deformations : volumic variations and transformation plasticity

Tensile test during continuous cooling

Time

Temp. .

Transform.

Deform.

DITHEM experiment

Thermomechanical behaviour during phase transformation

bainitic transformation Steel 40CrMnMo8

Constant cooling rate Deformation rate : 10-4 s-1

Temperature

PhD J. Ch. Louin 1998

Take into account the different sources of deformations d!ij

t=d!ije+d!ij

p+d!ijth+d!ij

tr+d!ijpt

-0,5

0

0,5

1

1,5

0 200 400 600 800 1000 1200D

éfor

mat

ion

(%)

Température (°C)

εijth = δij Σ yk α(T) dT

α(T) thermal expansion coefficients of the phases

εijtr = yk Σ εk

tr0°C

Continuous cooling dilatometry 35MnV7 steel (PhD M. Veaux)

Macroscopical phenomenological approach

Thermal strain

Transformation strain (volumic variation)

Elastic strain dεij

e Hooke’s law E, ν = f (temperature, microstructure) Mixture law plastic/viscoplastic strains : classical theory, Von Mises yield criterion and associated flow rule, isotropic- kinematic hardening rules

Macroscopical phenomenological approach

For each phase σk = σ0k + Hk εvp

nk + Kk εvpmk

σ0(T) threshold stress hardening : H(T), n(T) viscous stress : K(T), m(T) for multiphase material : mixture law σ = Σykσk

.

d! ijt = d! ij

e + d! ijp + d! ij

th + d! ijtr + d! ij

pt

Thermomechanical behaviour of the different phases/constituents at different temperatures and strain rates

austenite 35MnV7 steel

0

200

400

600

800

1000

1200

0

0 , 5

1

1 , 5

2

0 500 1000 1500 2000

TempératureContrainte

Déformation

Tem

péra

ture

(°C

)/Con

train

te (M

Pa)

Déform

ation (%)

Temps (s)

Transform

Time

Température Example : thermomechanical behaviour of bainite

Steel 35MnV7 Austenitization 1100°C 10 min Bainite formed at 350°C/450°C tensile test at 200°C, 20°C

500

600

700

800

900

1000

1100

0 100 200 300 400 500

formée à 350°Cformée à 450°C

Sig

0,2%

(MPa

)

Température (°C)

350°C

450°C

Yield stress (0.2%) bainitic microstructures

thickness of bainite plates 0,057µm at 350°C 0,239 µm at 450°C

Elastic strain dεij

e Hooke’s law E, ν = f (temperature, microstructure) Mixture law plastic/viscoplastic strains : classical theory, Von Mises yield criterion and associated flow rule, isotropic- kinematic hardening rules

Macroscopical phenomenological approach

For each phase σk = σ0k + Hk εvp

nk + Kk εvpmk

σ0(T) threshold stress hardening : H(T), n(T) viscous stress : K(T), m(T) for multiphase material : mixture law σ = Σykσk

.

question : strain hardening full or partial loss of memory during phase transformation? (Sjöström, Leblond, Taleb…)

d! ijt = d! ij

e + d! ijp + d! ij

th + d! ijtr + d! ij

pt

Modelling of transformation plasticity

- Phenomenological approach: Experimental evolution law (uniaxial stress) : εpt = Kk σ f(yk) Generalization to triaxial stress states : assumption dεpt proportional to stress deviator Giusti

dεpt

ij = 3/2 Kk f’(yk)dyk sij

holds when the mechanism only plastic accommodation For diffusional transformation : - no experimental results under mutiaxial stresses - validation by micro - macro approaches Leblond, Fischer, Sjöström, Ganghoffer, Barbe

For martensitic transformation : - experimental results : transform. plasticity larger under tensile stress than under compressive stress Videau - micromechanical approach show clearly strong dependency on local stresses Wen

formulation of a macroscopical law still an open question (N phase model, Cailletaud 2004)

Experimental validation of the macroscopical behaviour law for steel

d! ijt = d! ij

e + d! ijp + d! ij

th + d! ijtr + d! ij

pt

PhD J. Ch. Louin

thermoelastoviscoplastic behaviour law σ = σ0 + H εvp

n + K εvpm

hardening = f(T) viscous stress = f(T)

threshold stress σ0 = σFe + σss + σ P + σ disl. σFe friction stress f (T) σss solid solution hardening f (T, composition ss) σ P precipitation hardening f (T, volume fractions and sizes of precipitates) σ  disl.hardening due to dislocation densities f (T, t)

0

500

1000

1500

0 0,5 1 1,5

5mn,Cal.5mn, Exp.30mn,Cal.30mn,Exp.1H,Cal.1H, ExP.2H, Cal.2H, Exp.4H,Cal.4H,Exp.

Déformation (%)

Steel 80MnCr5

Modelling of the thermomechanical behaviour during precipitation

Precipitation model

PhD Y. Wang 2006 (steel)

Tempering at 500°C Tensile test 20°C

PhD Godard 1999 (Al)

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

Process (cooling)

DEFORMATION

Heat conduction equation : div (λgradT) + qtr = ρcp δT/δt

- qtr power density associated with phase transformations

Modelling of heat transfer in the solid

- mixture laws for thermophysical properties

λ=∑ λkyk

qtr = ∑ΔHk dyk/dt

yk volume fraction of phase k cp=∑ cpkyk ρ=∑ ρkyk

Example : steel 35MnV7 Thermophysical properties

400

600

800

1000

1200

1400

0 200 400 600 800 1000 1200

austénite phases ferritiques

Cap

acité

cal

orifi

que

(J/k

g/K

)

Température (°C)

3

4

5

6

7

8

9

10

0 200 400 600 800 1000 1200

chauffagerefroidissement

Diff

usiv

ité th

erm

ique

(mm2/s

)

Température (°C)

15

20

25

30

35

40

0 200 400 600 800 1000 1200

austénite bainite

Con

duct

ivité

ther

miq

ue (W

/m/°

C)

Température (°C)

Thermal diffusivity ( « flash method »)

Specific heat (DSC)

Thermal conductivity

Heat conduction equation : div (λgradT) + qtr = ρcp δT/δt

- surface boundary condition for quenching : Φ = -λ (∂Τ/∂n) = h (ΤS - Τ∞)

- qtr power density associated with phase transformations

Modelling of heat transfer in the solid

- mixture laws for thermophysical properties

λ=∑ λkyk

qtr = ∑ΔHk dyk/dt

yk volume fraction of phase k cp=∑ cpkyk ρ=∑ ρkyk

Heat transfer in vaporizable fluids (water, oil, …)

h (surface temperature, temperature and agitation of the bath, surface state, position of the piece …) difficult to determine inverse methods

0

200

400

600

800

1000

1200

0 20 40 60 80 100

2,5 mm7,5 mm12,5 mmCentre

Tem

péra

ture

(°C)

Temps (s)

0

2000

4000

6000

8000

10000

12000

14000

16000

0 200 400 600 800 1000 1200

Eau froideHuile froideAtmosphère contrôlée

h (W

/m2 /°C

)

Température (°C)

Ex : quenching in cold water (cylinder diameter 35mm length 105 mm steel 35MnV7

PhD Veaux

Heat conduction equation : div (λgradT) + qtr = ρcp δT/δt

- surface boundary condition for quenching : Φ = -λ (∂Τ/∂n) = h (ΤS - Τ∞)

- qtr power density associated with phase transformations

Modelling of heat transfer in the solid

- mixture laws for thermophysical properties

λ=∑ λkyk

qtr = ∑ΔHk dyk/dt

yk volume fraction of phase k cp=∑ cpkyk ρ=∑ ρkyk

most often : inverse methods to determine h(Ts) (due to the complexity of heat transfer mechanisms

particularly in vaporizable fluids)

Promising approaches : coupling with fluid flow simulations gaz quenching heating in furnace

Modelling of flow and heat transfer in the gaz (code Fluent) Solution of equations - Navier-Stokes

- continuity - heat transport - turbulence transport : chosen model : k-ω

thermophysical properties of gaz: dynamic viscosity, thermal conductivity, density, specific heat

Prediction of the local wall heat transfer coefficient distributions surface boundary condition for the solid :

Φloc = -λ (∂Τ/∂n) = hloc (Τp - Τ∞)

h T

Δtf

Δtc Unsteady simulation in the solid phase

Unsteady simulation in the gas phase

Coupling between FLUENT and SYSWELD

Coupling with simulations in the solid

J.F. Douce, J.P. Bellot, S. Denis, F. Chaffotte, G. Pellegrino HTM 61 (2006)

Fluid – thermal – metallurgical – mechanical couplings in heat treatment

FLUID FLOW material

Process (cooling)

DEFORMATION

2 examples : gaz quenching quenching and tempering

Cylinder Stand

Uniform Mass Flow Inlet

Outflow Wall

VirtualWall : no shear, zero heat

flux

Support

Walls 1 cm

r x

Heat Exchanger

fan

viewport

furnace

quenching cell

Application example : gaz quenching Experimental device from Ecole des Mines d’Albi

30 mm

80 mm 12

67

3

4

5

67

54

3 21

2 mm 6,5 mm

Coupe AA

J.F. Douce, J.P. Bellot, S. Denis, P. Lamesle, F. Gouhinec, F. Chaffotte, G. Pellegrino, Int. J. Microstructures and Material Properties Vol.3, n°1, 2008

-  nickel -  27MnCr5 steel

A

C

D

1 2

4.5 bar helium gaz quenching velocity vectors

experimental calculated

Heat transfer coefficient distribution along lateral surface

4.5 bar helium gaz quenching of a nickel cylinder

0

100

200

300

400

500

600

700

800

900

1000

0 50 100 150 200 250 300 350 400 450 500 550 600 650temps (s)

tem

p?ra

ture

(¡C

)

10 mm milieu70 mm milieu10 mm milieu (mod?lisation )70 mm milieu (mod?lisation )

Temperature evolutions measured- calculated

bottom

top (10mm) r=6,5 mm

bottom (10mm) r = 6,5 mm

calculation.

gaz

In-situ measurements of the deformation

Ext. diam. : 40mm Height : 70mm

gaz

27MnCr5 steel

Dissertation J.F. Douce, 2008

Comparison measurements - calculation

Radius variation (mm)

Final shape

Distributions of microstructures Residual stresses

Hardness

axial stress hoop stress

0

200

400

600

800

1000

0 50 100 150 200

CentreSurface

Temps (s)

-1200

-800

-400

0

400

0 50 100 150 200

!z, Centre

!z, Surface

Temps (s)

Chain different processes : quenching + tempering (FE code ZeBuLon)

cylinder Φ 35mm L 105 mm steel 60NiCrMo11 martensitic quenching from 900°C to 20°C tempering 10°C/s 600°C

Axial stress evolution

Temp t=10s

Martensite t=10s

PhD Y. Wang , Nancy, 2006

Ms Ms

Quenching

Calculated loading paths

Von Mises stress σe equivalent plastic strain εe

p = √2/3 εijpεij

p

equivalent total strain εe

t = √2/3 εijtεij

t

S. Denis et al, Mat Sci Technol 1985

Role of transformation plasticity during quenching

Residual stress profiles after water quenching Role of stress – phase transformation

interactions

S. Denis et al, Mat Sci Technol 1985

-400

-300

-200

-100

0

100

200

0

100

200

300

400

500

600

150 160 170 180 190 200 210 220

!z, centre, avec trans. de phase

!z, surface, avec trans. de phase

!z, centre, sans trans. de phase

!z, surface, sans trans. de phase

!0, centre

!0, surface

Temps (s)

0

200

400

600

800

1000

0

100

200

300

400

500

600

700

800

150 160 170 180 190 200 210 220

!0

!ss

!ps

!ds

!fsTempérature

Temps (s)

Relaxation of quenching residual stresses during tempering

surface

centre

PhD Y. Wang , Nancy, 2006

-300

-200

-100

0

100

200

0 0.005 0.01 0.015 0.02

150s170s190s210s215s

Rayon (m)

Evolutions of stress profiles during tempering

-200 -120 -40 0 40 100 160

End of quenching

End of heating

X20

PhD Y. Wang , Nancy, 2006

Conclusion - Future developments

• Material point of view - metallurgical models

. global models work for industrial metallic alloys and complex situations prediction of volume fractions . models including nucleation and growth develop more and more

for multicomponent alloys volume fractions and morphological parameters

allow prediction of mechanical properties (Al alloys, Ti alloys…)

. take into account chemical composition gradients (carburizing, carbonitriding, solidification segregations) . effects of prior plastic deformations, effect of stresses

- thermomechanical behaviour with phase transformations

. phenomenological laws exist extension to other metallic alloys (Ti alloys…)

better description of multiphase material (morphology) micro-macro approaches must be further developped

Conclusion - Future developments

• Heat treatment processes -  coupling between fluid and solid : developments for vaporizable fluids (experiments and modelling) -  include heating processes (furnace, induction…) -  in situ measurements (solid + fluid) for rapid processes -  chain different processes : liquid metal processing + solidification + forming + heat treatment… • Numerical aspects

Two review papers S. Denis, Revue de Métalurgie CIT/SGM, février 1997, pp. 157-176 S. Denis, P. Archambault, E. Gautier, A. Simon, G. Beck, JMEPG Vol 11 (1), 2002, pp. 92-102

Common work with A. Simon, E. Aeby-Gautier, P. Archambault, J.P. Bellot, B. Appolaire PhD students : FMB Fernandes, C. Basso, J.P. Josserand, D. Farias, F. Saliou, M. Boufoussi, J.F. Ganghoffer, Y. Wen, L. Massicart, M. Zandona, A. Mey, P. Brunet, C. Aubry, J. Ch. Louin, M. Veaux, Y. Wang, Y. Renault, J.F. Douce, M. Haering, L. Mangin, S. Devynck, S. Catteau… In the frame of industrial collaborations CETIM, ARBED, UNIMETAL RECHERCHE, PSA, RENAULT, Creusot Loire Industrie, French Programme SIMULFORGE, European programme VHT, Ascometal, Air Liquide, SNR, Vallourec, ...