1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and...
-
Upload
chester-hoover -
Category
Documents
-
view
216 -
download
0
Transcript of 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and...
![Page 1: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/1.jpg)
1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Processo Q&P (Quenching and Partitioning)
Estudo de caso completo
Fernando Rizzo
![Page 2: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/2.jpg)
2 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Projeto de Cooperação Internacional
J.G. Speer, D.K. Matlock , A. Streicher
– Colorado School of Mines, USA
F. Rizzo, A. R. Aguiar
– PUC, Rio de Janeiro, Brazil
D.V. Edmonds, Kejian He
– University of Leeds, UK
NSF-CNPq (CIAM) , NSF-EPSRC
![Page 3: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/3.jpg)
3 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Quenching and Partitioning:
- Background
- Fundamental Issues
- Recent Results
•J.G. Speer, D.K. Matlock, B.C. De Cooman and J.G. Schroth, Acta Mater., 51 (2003) 2611-2622. •J.G. Speer, A.M. Streicher, D.K. Matlock, F.C. Rizzo and G. Krauss, Austenite Formation and Decomposition, ed. E.B. Damm and M. Merwin, TMS/ISS, Warrendale, PA, USA, 2003, pp. 505-522. •John G. Speer, David V. Edmonds, Fernando C. Rizzo, David K. Matlock, Current Opinion in Solid-State and Materials Science, 8 (2004) 219-237
![Page 4: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/4.jpg)
4 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
TRIP SteelsMF
Ac3
Time
Te
mp
era
ture
MS
Ac1
B +
C
iC
f
“Conventional”Processing ofSteels with
CC and Isothermal
Transformations
Ac3
Te
mp
era
ture
C = Ci
MF
Time
MS
B +
![Page 5: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/5.jpg)
5 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
The “Q&P” ProcessQuenching and Partitioning
TE
MP
ER
AT
UR
E
TIME
PT,t
AT
QT
Quenchedand Partitioned
Ms
Mf
Provisional US Patent Application: September, 2003
![Page 6: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/6.jpg)
6 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
The “Q&P” Process
Step 1. Austenitize or Intercritically Anneal
- more austenite- lower C
- higher Ms
- less austenite- higher C
- lower Ms
![Page 7: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/7.jpg)
7 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Step 2. Cool (quench?) below Ms
- Ms -TQ controls martensite formation
- intercritical annealing has more stable austeniteand higher carbon martensite
Austenitize + Quench Intercritical Anneal + Quench
![Page 8: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/8.jpg)
8 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Step 3. Diffuse Carbon from Supersaturated Martensite
- Phase compositions change
- Phase boundaries stationary
![Page 9: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/9.jpg)
9 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Q&P Process Schematic
![Page 10: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/10.jpg)
10 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
New Processing Concept (Sheet, Bar,…etc)
Use carbon partitioning intentionally…from partially transformed martensite tountransformed austenite.
Usually precluded because carbide precipitation occurs during tempering of martensite.
Result: carbon-enriched austenite
![Page 11: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/11.jpg)
11 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Thermodynamics of Carbon
Partitioning
![Page 12: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/12.jpg)
12 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Important Questions
How much can we enrich the austenite?
That is…what are the “equilibrium” martensite and austenite compositions?
Or…when does partitioning stop?
![Page 13: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/13.jpg)
13 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
“True” Metastable Equilibrium
Fe3C
% Carbon
Tem
per
atu
re
Fe3C
![Page 14: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/14.jpg)
14 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
“True” Metastable Equilibrium
Fe C
G
xEQ
FeFe
CC
xEQ
![Page 15: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/15.jpg)
15 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
“True” Metastable Equilibrium CANNOT Apply!!
Fe3C
% Carbon
Tem
per
atu
re
Fe3C
XalloyX X
- The equilibrium phase fractions are fixed by the lever rule- The actual phase fractions were fixed by cooling below Ms!
![Page 16: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/16.jpg)
16 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
A New Equilibrium Condition was Hypothesized
“Constrained Carbon Equilibrium” (CCE)
- Iron atoms are completely immobile (the phase boundaries are stationary).- Carbon atoms are completely mobile.- Carbon diffuses until its chemical potential (activity) is equal in ferrite and austenite.- Assume…competing reactions are precluded by
Si/Al
![Page 17: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/17.jpg)
17 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Properties of “Constrained Carbon Equilibrium”
- Not a unique condition at any temperature!- Depends on initial phase fractions/compositions
Fe C
G
II
C
II
C
xI
CPE
x
II
CPE
xI
CPE
x
II
CPE
I
C
I
C
![Page 18: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/18.jpg)
18 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
- Austenite may be more enriched or less enriched than ortho- or para- equilibrium
Fe C
G
II
C
II
C
xI
CPE
x
II
CPE
xI
CPE
x
II
CPE
I
C
I
C
T0
A3
Properties of “Constrained Carbon Equilibrium”
![Page 19: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/19.jpg)
19 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Properties of “Constrained Carbon Equilibrium”
RT
TT
CC
CCEC
CCECCEe
X)4.120105,169(8.43789,76
XX
XXX alloyCCCCECCCE CCECCE
ff
)X1()X1( iCCE CiCCCE ff
Carbon Constrained Equilibrium:
Mass balance:
![Page 20: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/20.jpg)
20 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Key Characteristics of CCE
- Almost all of the carbon should partition to austenite- Enrichment levels are potentially very high
(Fe-0.5C)
![Page 21: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/21.jpg)
21 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Example CCE Calculations - 1.0%C Initial Austenite
M artensite C ontent25%50%75%90%
1x10 - 4 1x10 - 2 1x10 0
Carbon in Ferrite (wt. % )
200
300
400
500
600
Tem
pera
ture
(oC
)
0 2 4 6 8 10
Carbon in Austenite (wt. % )
200
300
400
500
600
1% Carbon
![Page 22: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/22.jpg)
22 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
We have all the pieces to predict microstructure…
Example
Steel Composition: C=0.15 Mn=1.0 Si=1.5
Ms(oC)=539-423(%C)-30.4(%Mn)-12.1(%Cr)-17.7(%Ni)-7.5(%Mo)
Ms=445oC (Steel)
Intercritical Annealing T=810oC
f~ 22% C~ 0.68 wt. % Ms~222oC
f~ 78%
TIA=810oC
![Page 23: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/23.jpg)
23 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Quench T = 150 oC
Fraction of Martensite(Koistinen and Marburger)
Final Microstructure
f~ 10%
fM~ 12%
f~ 78%
Phase Compositions After 450oC Partitioning
C~ 1.5%
CM~ .0019%
Tq=150oC
Tp=450oC
fkm 1 exp 1.1 102 Ms Tq
![Page 24: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/24.jpg)
24 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Q&P Process Design Methodology
Experimental High-Al TRIP Sheet Steel C Al Mn Si P N Cr S
0.19 1.96 1.46 0.022 0.01 0.0018 0.08 0.002
ASSUME:
- Complete partitioning of carbon to austenite
- No competing reactions (carbide formation)
![Page 25: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/25.jpg)
25 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Calculations for Experimental Al-Steel (at QT)
0 100 200 300 400
Q uench Tem perature
0
0.1
0.2
0.3
0.4
0.5
Pha
se F
ract
ion
M in itia l quench in itia l quench
AlSiMnCCo 305.74.30423539)(M s
IA=0.5
![Page 26: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/26.jpg)
26 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Martensite Formation During Final Quench
0 100 200 300 400
Q uench Tem perature
0
0.1
0.2
0.3
0.4
0.5
Pha
se F
ract
ion
M in itia l quench
M fina l quench
in itia l quench
![Page 27: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/27.jpg)
27 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Calculated Final Austenite Fraction in High-Al Steel
final
0 100 200 300 400
Q uench Tem perature
0
0.1
0.2
0.3
0.4
0.5
Pha
se F
ract
ion
M in itia l quench
M fina l quench
in itia l quench
![Page 28: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/28.jpg)
28 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Effect of Intercritical Annealing Step
0 100 200 300 400 500
Q uench Tem perature - oC
0
0.05
0.1
0.15
0.2
0.25
Fin
al A
uste
nite
Fra
ctio
n
IC = 0%
IC = 50%
IC = 75%
![Page 29: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/29.jpg)
29 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Effect of Manganese Content
0 100 200 300 400 500
Q uench Tem perature - oC
0
0.05
0.1
0.15
0.2
0.25
Fin
al A
uste
nite
Fra
ctio
n
0.5% M n1.46% M n
![Page 30: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/30.jpg)
30 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Effect of Carbon Content
![Page 31: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/31.jpg)
31 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Example of DICTRA SimulationSolid-Solid Phase Transformations in Inorganic Materials 2005
Edited by J. HoweTMS (The Minerals, Metals & Materials Society), 2005
CARBON ENRICHMENT OF AUSTENITE AND CARBIDE PRECIPITATION DURING THE QUENCHING AND
PARTITIONING (Q&P) PROCESS
F.C. Rizzo 1, D.V. Edmonds2, K. He 2, J.G. Speer3, D.K. Matlock3and A. Clarke 3
1Department of Materials Science and Metallurgy; Pontifícia Universidade Católica-Rio de Janeiro; RJ 22453-900, Brazil
2School of Process, Environmental and Materials Engineering; University of Leeds; Leeds LS2 9JT, United Kingdom
3Advanced Steel Processing and Products Research Center; Colorado School of Mines; Golden, CO 80401, USA
![Page 32: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/32.jpg)
32 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Simulation Conditions
Steel composition:
•0.19C-1.59Mn-1.63Si wt%
Heat treatment:
•Fully austenitized at 900oC, quenched to 293oC to produce 68% martensite and partitioned at 400oC. The thickness of the ferrite and austenite plates used in the simulation were 0.30 and 0.14 microns, respectively (obtained by TEM).
![Page 33: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/33.jpg)
33 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Carbon Concentration Profiles for ferrite and austenite
0
400
800
1200
1600
2000
2400
2800
3200
AC
R(C
)
0 5 10 1510-8
DISTANCE
DICTRA (2005-07-01:11.46.47) :Ferrite C activityTIME = 1E-04,.001,.01,.1,1,10
CELL #2
2005-07-01 11:46:47.76 output by user Fernando from RIZZO1
0
5
10
15
20
25
30
10-3W
(C)
0 1 2 3 4 5 6 710-8
DISTANCE
DICTRA (2005-07-01:11.59.50) :Austenite C ProfileTIME = 1E-04,.001,.01,.1,1,10
CELL #1
2005-07-01 11:59:50.50 output by user Fernando from RIZZO1
![Page 34: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/34.jpg)
34 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Carbon concentration profiles in and during partitioning under CCE at 400C, for a 0.19C-1.59Mn-1.63Si steel
![Page 35: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/35.jpg)
35 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Average carbon concentration as a function of time for
(0.30m) and (0.14m) plates during partitioning at 400oC
![Page 36: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/36.jpg)
36 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Variation of (a) carbon flux and (b) carbon activity at the interface during partitioning. Time plotted in a log scale
![Page 37: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/37.jpg)
37 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Carbon concentration (wt%) at and interfaces as a function of time during partitioning at 400 oC
![Page 38: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/38.jpg)
38 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Carbon flux and concentration in the center of (a) ferrite and (b) austenite plates as a function of time
![Page 39: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/39.jpg)
39 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
CONCLUSIONS
1. For the scale of microstructure investigated, carbon depletion from the ferrite during partitioning at 400C occurs quite rapidly, around 10-1 seconds, while the austenite takes much longer, around 10 seconds, to achieve a uniform concentration.
2. Due to its rapid depletion, the carbon concentration in the center of the ferrite plate starts to decrease after 10-3 seconds. After this time the driving force for carbide precipitation is gradually reduced.
3. Carbon enrichment of the austenite will promote, initially, a substantial increase in the carbon concentration at the interface and a progressive stabilization of the plate, advancing from the interface to the center. Full stabilization is achieved when the composition of the central region reaches a carbon concentration corresponding to room temperature Ms.
![Page 40: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/40.jpg)
40 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Some Q&P Experimental
Results
![Page 41: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/41.jpg)
41 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
TEM micrographs of the Q&P microstructure produced in a 0.19%C-1.59%Mn-1.63%Si TRIP steel composition
Quenching to 260°C and partitioning at 400°C for 100 s: (a) bright-field image and (b) dark-field image using a (200) austenite reflection.
(a) (b)
![Page 42: 1 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012 Processo Q&P (Quenching and Partitioning) Estudo de caso completo Fernando Rizzo.](https://reader036.fdocumentos.com/reader036/viewer/2022062515/56649cff5503460f949d002f/html5/thumbnails/42.jpg)
42 Workshop Aplicações da Termodinamica Computacional a Siderurgia 2012
Total elongation vs. ultimate tensile strength for TRIP, Dual phase (DP), martensitic (M), and Q&P sheet steel products
400 800 1200 1600U ltim ate Tensile S tre ng th , M Pa
0
10
20
30
40T
ota
l Elo
ng
atio
n,
%TRIP (ULSAB)A
TRIP (GM )A
Conventional TRIPB
1-Step Q&PB
2-Step Q&PB
M (ULSAB)A
M (GM)A
M (Ispat-In land)C
DP (ULSAB)A
DP (GM )A
DP (Ispat-Inland)CT R IP
D P
M
Q & P
Note A: 80 mm gauge lengthNote B: 25.4 mm gauge length Note C: Gauge length unspecified