Nanostructured Steel Industrialization: a plausible

reality C. Garcia-Mateo, T. Sourmail, F.G. Caballero, V. Smanio, C.

Ziegler, M. Kuntz, R. Elvira, A. Lerio, E. Vuorinen, T. Teeri cgm@cenim.csic.es

Acknowledgements:    APM  2013  Conference  Chair  European  RFCS.  RFSR-­‐CT-­‐2008-­‐00022    MINECO  MAT2010  -­‐  15330  

CENIM-CSIC ASCOMETAL

ALD BOSCH

GERDAU LTU

METSO

=

CSICCENTRO  NACIONAL  DE  INVESTIGACIONES  METALÚRGICAS   (CENIM)

Bhadeshia´s  bainite  phase  transforma2on  theory  

Time

Isothermal transformation

hours-monthsslow cooling

Air cooling

AustenitisationHomogenisation

Bs

Ms

Alloy    Design  process  

200ºC  10d  

γ  à  αb  

High  density  strong  interfaces  nano  α+γ    

Displacive  (Disloca2ons,  Nano-­‐  twins)    &  Diffusionless  

200  oC  for  2  days.   Caballero  .  Acta  2010  &  2011  

 Very  different  C  content  

 as   size  ò  è  ñ  C  è  beGer  mechanical  

response  

Austenite  morphologies  

Garcia-Mateo, et.al. Journal of Materials Science 2012, Bhadeshia, et al. Metal Science 1983,

1   µ m

50610347 .)(. ρσΔ −≅1(2t)115Δσ −≅

Garcia-Mateo & Caballero, (2005 & 2007)

Big  poten+al  foreseen    0

5

10

15

20

25

30

0 500 1000 1500 2000 2500

Uniform

 Elong

ation/  %

Yield  Strength/  MPa

Ref  1

Ref  2

Ref  3

Ref  4

Ref  5

Ref  6

Ref  7

Nano  1

Nano  2

Nano  3

MartensiteECAP

Warm  defFriction  Stir  processing

ATMP

NANOBAIN

UTS >  2  GPa

                 

R+D    

Steel  Makers  

Final  User  

IndustriallizaOon  of  NANOBAIN  

Carbide  free  microstructure  

Simple  alloy  system    

Reasonable  transforma2on  2me  

Hardenabillity  700  x400x250  mm3è  Salt  bath    200x20x30  mm3è  DryBainTM  

High  frac2on  of  baini2c  ferrite  

Low  transforma2on  temperatures  

Fundamental  &  Industrial  Design  ConsideraHons    

Addi2on  of  1.5Si  wt.%  

Fe-­‐C-­‐Si-­‐Mn-­‐Cr  

Reduc2on  of  PAGS  

Vα  =  f(To  line,T)  

α→γΔG

{ } ααγ ʹ′→ <Δ Ns GMGBs   Ms  

Approach  

0

10

20

30

40

50

60

70

80

90

100

2013 NANOBAIN grades

Vb/ % t/ nm250ºC 240ºC 250ºC 250ºC 250ºC270ºC

C Si Mn Cr Mo Nb0.99 1.58 0.76 0.451.00 1.53 0.75 0.51 0.021.01 1.51 0.82 0.46 0.0960.98 2.90 0.77 0.450.88 1.54 0.69 0.500.67 1.6 1.25 1.500.61 1.45 0.76 2.420.64 1.60 1.27 1.5 0.030.58 1.63 1.29 1.43 0.1

NANOBAIN  steel  

Simple  alloy  system    ü  

Low  transforma2on  temperatures  ü  

(220ºC-­‐350ºC)  

NANO  (plate  thickness  t)  ü  

High  frac2on  of  baini2c  ferrite  (Vb)  ü  

1

10

100

190 240 290 340

Tim

e to

tran

sfor

m /

h

Temperature / ºC

1CSi

1CNb

1C

08C

B.A. @200ºC

B.A. @250-300ºC

1CMo

0

100

200

300

400

500

600

700

800

900

1 10 100 1000

Tem

pera

ture

/ ºC

Time/ s

CCT DIAGRAM - 950ºC - 1CSiCR/ ºC/s

P

M

1.551020 350 Ac1=820 ºCAc3=844ºCMs= 165ºC

803 827 721 512

442449 HV

Faster  transforma2on  ü  

Suffice  hardenabilityü  

100 nm 1CSi  250ºC  16  h  

γ

γ

αα

0

5

10

15

20

25

30

0

500

1000

1500

2000

2500

Elongation/ %S

treng

th/ M

Pa

Steels

YS UTS Uniform Total250ºC 240ºC 250ºC 250ºC 250ºC270ºC

Strength  /  DucHlity  (Tensile  test)  

UTS  >  2  GPa  

Twin  discs  wear  test,  100  rpm,  5%  slip,  300N  load,  5h  

Wear  properHes  :  rolling-­‐sliding  wear  tests  

0,0E+00

1,0E-04

2,0E-04

3,0E-04

4,0E-04

5,0E-04

6,0E-04

7,0E-04

200 300 400 500 600 700 800

Hardness (HV0.5)

SWR

(mm

3 /N.m

)

1C-250C1CSi-250C08C-220C08C-250C08C-270C06C-250C06CMo-250C06CNb-250C1CSi-ind 220C06CV-220C06CV-280C100Cr6-std100Cr6-950C-250C100Cr6-950C-300C40CrSi860CrSi960SiCr7-25060SiCr7-30060SiCr7-35060SiCr7-N42CrMo4-B35042CrMo4-B40042CrMo4-QT

NANOBAIN  

B+C  

B  

B+C  

P  B+C  B  M  

NANOBAIN  

P  

P  

M  

 Wear  298-­‐299,  42-­‐47  (2013).  

Wear  properHes  :  high  pressure  abrasion   200N  Δt  =  2.5s  t  =  30  min  

 Hardox  (SSAB)  0.3C-­‐0.7Si-­‐1.6Mn-­‐1.5Cr-­‐1.5Ni-­‐0.6Mo  (%wt.)  HV  =  500  ;  Tempered  Martensite+  austenite  

024681012141618

0

0.5

1

1.5

2

2.5

KV/  J

Relativ

e  HP

A  wear  (ref:  Ha

rdox  500

)

HPA KV

Hardox

0

5

10

15

20

25

30

35

Toughn

ess  x

 Relative  HP

A  wear  (ref:  

Hardox  500

)Hardox

FaHgue  properHes  :  rotaHon  bending  on  notched  specimens.  

Condition UTS / MPa Sa, 50% at 107 cycles / MPa for R = -1,

Kt = 1,6 by rotation bending

1CNb-220-FAT 2073 430

06C-250-FAT 2023 665

08C-270-FAT 2036 440

1CSi-ind-220-FAT 2224 550

1CSi-ind-250-FAT 2072 535

06CV-ind-250-FAT 2003 690

06CV-ind-270-FAT 1822 675

Notch  ?  -­‐ApplicaOon  have  stress  

concentrator    

-­‐FaOgue  sensiOve  to  austenite  decomposiOon  

0.6C  @250ºC  

(Industrial)  Material    selecHon  

Strength  duc2lity  balance  è  small  component  è    1CSi    

HPA+Charpy  performance    è  big  component  (hardenability)  è  0.6  CNb    

0.6  CNb  ó    0.6  CV    

=  microstructure,    HV  &  Bs/  Ms  +  faster  kineOcs    

C Mn Si Cr Mo V 1CSi-ind 1.00 0.75 2.50 1.00 0.03 0.00

0.6CV-ind 0.60 1.25 1.60 1.75 0.15 0.12

Industrial  heats  casted  

Before  fabrica2ng  a  component  or  demonstrator  

Ba_ery  of  tests  

Tensile    Industrial  Material  

0

500

1000

1500

2000

2500

Stre

ngth

/ M

Pa

Yield Strength / MPaTensile Strength / MPa

0.00

5.00

10.00

15.00

20.00

25.00

Elon

gatio

n / %

Uniform elongation / %

Elongation at fracture / %

0

500

1000

1500

2000

2500

Stre

ngth

/ M

Pa

Yield Strength / MPa

Tensile Strength / MPa

0.00

5.00

10.00

15.00

20.00

25.00

Elon

gatio

n / %

Uniform elongation / %

Elongation at fracture / %

Twin  discs  wear  test,  100  rpm,  5%  slip,  300N  load,  5h  

Wear  :  rolling-­‐sliding  wear  tests  

0,0E+00

1,0E-04

2,0E-04

3,0E-04

4,0E-04

5,0E-04

6,0E-04

7,0E-04

200 300 400 500 600 700 800

Hardness (HV0.5)

SWR

(mm

3 /N.m

)

1C-250C1CSi-250C08C-220C08C-250C08C-270C06C-250C06CMo-250C06CNb-250C1CSi-ind 220C06CV-220C06CV-280C100Cr6-std100Cr6-950C-250C100Cr6-950C-300C40CrSi860CrSi960SiCr7-25060SiCr7-30060SiCr7-35060SiCr7-N42CrMo4-B35042CrMo4-B40042CrMo4-QT

NANOBAIN  (LAB)  

NANOBAIN  (IND)  

Wear  properHes  :  high  pressure  abrasion  

0

5

10

15

20

25

30

35

Toughn

ess  x

 Relative  HP

A  wear  (ref:  

Hardox  500

)

Hardox

0.6CV  280ºC  

0.6CV  220ºC  

FaHgue  properHes  :  rotaHon  bending  

Condition UTS / MPa Sa, 50% at 107 cycles / MPa for R = -1, Kt = 1,6 by rotation bending

1CNb-220-FAT 2073 430

06C-250-FAT 2023 665

08C-270-FAT 2036 440

1CSi-ind-220-FAT 2224 550

1CSi-ind-250-FAT 2072 535

06CV-ind-250-FAT 2003 690

06CV-ind-270-FAT 1822 675

0.6CV  @270ºC  

FaHgue  properHes  :  notched  tension-­‐tension  specimens  

06CV-250 06CV-270 1CSi-220 1CSi-250

100Cr6[TLi, 1998]

50CrMo4[SSc, 2012]

UTS / MPa 2003 1822 2224 2072 2350 1180

Sa,50% at N = 107

cycles / MPa350 330 205 245 355 305

RepresentaOve  of  the  funcOoning  of  heavily  loaded  diesel  engines  

Kt  =  2  R  (stress  raOo)  =    0.1  

150Hz  

Small  component  High  pressure  injecHon  (demonstrator)  

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

1,0E +04 1,0E +05 1,0E +06 1,0E +07 1,0E +08

Internal  Pulsa

ting  am

plitu

de  Δp  /  b

ar

Number  of  c yc les  to  failure,  Nf

3

06C V-­‐250  1C S i-­‐250

Big  component    Scrap  shear  blades  (component)  

0.6CV  @  280ºC  

Estimated potential gain 20%

due to the significantly cheaper material

524x80x200  mm3    

•  Design   of   ‘cheap’   steel   grades   adapted   to   low   temperature  bainiHzing  and  applicaHon  hardenability  .    

•    Tensile   properHes   :   achieved   excellent   combinaHons   of   high  strength  and  ducHlity.  Unprecedented  and  unexpected  21%  TE  at  UTS  2GPa.  

•    FaHgue   tests,   on   par   with   100Cr6   for   one   of   the   industrial  grades,  scope  for  improvement  

•   Large   improvement   in  RS  wear  resistance,  related  to  retained  austenite  decomposiHon  

Conclusions  

Achievement  In   just   over   three   years,   the  Nanobain   project   took   the  concept   of   nanostructured   bainiOc   steels   from   a  laboratory  experiment   to   full   scale   industrial  producOon  and  tesOng.      

Solely  by  means  of  phase  transforma+on  theory.