The EUROfusion program on 9CrWVTa steels M. Rieth, P. Fernandez, J. Henry, J. Hoffmann, L. Pilloni, A. Puype, N. de Wispelaere
The EUROfusion program on 9CrWVTa
steels
M. Rieth, P. Fernandez, J. Henry, J. Hoffmann, L. Pilloni, A. Puype, N. de Wispelaere
Budget (w/o overheads)
2 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
0
500
1000
1500
2000
2500
1 2 3 4 5
Hardware (EC/k€) Total Allocated2014-18
2300
2400
2500
2600
2700
1 2 3 4 5
Manpower (EC/k€) Total Allocated2014-18
Total Allocated Resources by RU
273 lab ppy 30 ind ppy
8.74 M€ hw
Overall Objectives 2014-2018
3 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Fill gaps in the database and develop design codes for the baseline materials including irradiation data
Development of new materials to mitigate requirements of advanced DEMO component designs
Demonstration of the production of such materials in processes scalable to industrial standards
Characterization & Documentation of the properties of such materials
Develop models for neutron radiation effects, specifically microstructural evolution and embrittlement, in iron alloys, steels, tungsten, and degradation of functional materials
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ODS steel: Fabrication & Demonstration Production of a 100 kg 14%Cr ODS steel batch by mechanical alloying
Plates: thickness 2 mm, size 2 m² Demonstration of applicability to first wall
Alternatives to mechanical alloying (feasibility studies and industrial large-scale fabrication)
Development of RAFM steels for high temperature applications Specific thermal treatments on EUROFER Special thermo-mechanical treatments (TMT) Fine tuning of the chemical composition
Optimization of RAFM steels for possible water cooling Specific thermal treatments (for optimum DBTT) Change of chemical composition (for optimum DBTT)
Advanced Steels (AS): Objectives
RAFM: Reduced Activating Ferritic-Martensitic
focus of this presentation
Effect of Extreme Heat Treatments: EUROFER
5 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Z and Laves phases suspended
0,0001
0,001
0,01
0,1
1
500 700 900 1100 1300 1500 1700980 1050 1150 760
Mo
lar
ph
ase
fra
ctio
n
Temperature (°C)
Liquide
(V,Ta)(N,C)
M23C6
TaN-
(Ta,V,Cr)(C,N)
Advanced Steels: High Temp. Applications
Adjustment of EUROFER properties by varying heat treatment temperatures
• Austenitisation: 980 °C – 1150 °C • Tempering: 700 °C – 760 °C
7 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Z and Laves phases suspended
0,0001
0,001
0,01
0,1
1
500 700 900 1100 1300 1500 1700980 1050 1150 760
Mo
lar
ph
ase
fra
ctio
n
Temperature (°C) 1250
Liquide
(V,Ta)(N,C)
M23C6
TaN-
(Ta,V,Cr)(C,N)
Effect of Extreme Thermo-Mechanical Treatments
Effect of Extreme Thermo-Mechanical Treatments
8 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Very high austenitization temperature for full dissolution of secondary phases Increase PAG size for improved creep strength (lower diffusion) Possible problem: Retain enough ductility at RT
Dissolution of all secondary phases (carbides, nitrides)
Cooling to rolling temperature in furnace (metastable
austenite phase)
Rolling in the austenite phase
Effect of Extreme Thermo-Mechanical Treatments
9 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Standard Heat Treatment
1050°C / 30min + 750°C / 2h
EUROFER
Very large prior austenite grains (0.5-1 mm) But fine martensite laths
1250°C/30 min + TMT at 800°C + 750°C / 2h
Extreme TMT
70 µm 70 µm
Effect of Extreme Thermo-Mechanical Treatments
10 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
gain of ~ 50 MPa in strength
0 100 200 300 400 500 600 7000
100
200
300
400
500
600
yie
ld s
trength
[M
Pa]
Temperature [°C]
Eurofer 97-2 (993391)
600°C
700°C
800°C
900°C
as-received
Tensile Strength
Effect of Extreme Thermo-Mechanical Treatments
11 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Creep Strength
20000 h
+50 MPa +50 °C
Effect of Extreme Thermo-Mechanical Treatments
12 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
DBTT Shift (Charpy)
Fine-tuning of Chemical Composition
13 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Objective(s): 1. Selection a of chemical compositions of 9%Cr RAFM steels
with the aim of improving high temperature properties (creep and creep fatigue properties in particular) as compared to standard Eurofer.
2. Determination of the hot rolling temperature range by using the obtained phase diagrams.
Method(s): The modified chemical compositions will be obtained on the basis of thermodynamic calculations of Mx-(C,N)y phases in 9Cr(1-2W)VTa steels. Contents in C, N, Ta, V will be varied and the influence of W and Ti will be assessed. JMatPro & ThermoCalc Software
Fine-tuning of Chemical Composition
14 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
EUROFER97 89Fe-9Cr-1.1W-0.5Mn-0.2V-0.14Ta-0.1C-0.02N Fe88.7-Cr9.64-W0.33-Mn0.51-V0.22-Ta0.04-C0.46-N0.08
Fine-tuning of Chemical Composition
15 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
(CrFe)23C6
(FeCr)2W
Cr2TaVN2
V5N4
TaC
EUROFER97 89Fe-9Cr-1.1W-0.5Mn-0.2V-0.14Ta-0.1C-0.02N Fe88.7-Cr9.64-W0.33-Mn0.51-V0.22-Ta0.04-C0.46-N0.08
Fine-tuning of Chemical Composition
16 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
TEM studies on aged Eurofer samples
30000 h, 550-600 °C: no Laves phase Fe52Cr15W33
WCr
11 µm
Fe
Comparison and correction: Simulation - Reality
Fine-tuning of Chemical Composition
17 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
TEM studies on aged Eurofer samples
30000 h, 550-600 °C: Is there Z phase Cr2TaVN2 ?
Cr Ta Fe V Ta Fe
M23C6
TaC
VN
TaC
Precipitation map under development Provides correction parameters for simulation
Fine-tuning of Chemical Composition
18 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
minimum for martensite formation?
0.03 % C
0.05 % C
0.1 % C
0.02 % C
M2
3C
6 (
mo
le %
) Carbon
Fine-tuning of Chemical Composition
19 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
Lave
s (m
ole
%) 3 % W
2 % W
1.5 % W
1 % W
Tungsten
Fine-tuning of Chemical Composition
20 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
maximum for a complete alpha-gamma transition?
Au
ste
nit
e (
mo
le %
) Tungsten
3 % W
2 % W
1.5 % W
1 % W
Fine-tuning of Chemical Composition
21 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
P92 OPTIFER-IVa
EUROFER97 1538
Comparison/Correlation of known properties/alloys
Fine-tuning of Chemical Composition
22 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
o Reduction of M23C6 decrease of C content but ensure Martensite formation targets: 0.03 – 0.06 %
o VN: adjustment of amount and onset target: 0.4 – 0.6 % start of formation: about 1250 °C (solution annealing) by variation of V and N
o TaC: “adjustment” of onset target: below 0.2 % start of formation: below VN by variation of Ta
o Isolate/identify effects of single elements
Mn, Si – “further purification” by removal
W possible increase of strength by addition
o …
Strategies for optimization: some examples
Summary and present status
• More than 30 heats produced by industry (80 kg each)
• Development of a computational model for the selection
of 9%Cr RAFM steels optimized for high temperature
application (Genetic Algorithm)
• Mechanical properties & microstructural investigations
under way irradiation in 2016/17
23 MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS
• CCFE • CEA • CIEMAT (+ CEIT,
URJC, UPM, …) • DTU • ENEA-Frascati • ENEA-CNR • FZJ • Wigner RCP (HAS) • NCSRD (HELLENIC) • MPG (IPP) • IPPLM • IST • KIT • ISSP-UL (LATVIA) • IAP (MEdC) • JSI (MESCS) • FOM-DIFFER (NRG) • OEAW • RBI • LPP-ERM-KMS
(SCK.CEN) • UT (TARTU) • VTT (TEKES) • VR
Thank you !
MATISSE Workshop | Petten | 25-25.11.2015 M. Rieth et al.: EUROfusion WPMAT-AS 24