Post on 15-Jul-2020
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.