Improvement of RAFM steels through thermo-mechanical treatments

*contact:
Jan Hoffmann
E‐Mail: j.hoffmann@kit.edu
Phone: +49 (0) 721 6082 3476
Improvement of RAFM steels through thermo‐mechanical
Materials and Process
Batch
W
Cr
Ta
Fe
EUROFER97‐2 993402
1.06
8.9
0.18
0.04
0.15
0.1
bal.
EUROFER97‐2 993391
1.08
8.83
0.2
0.02
0.12
0.1
bal.
Dissolution of all secondary phases  Cooling to rolling temperature in 
(carbides, nitrides)
furnace (metastable austenite phase)
Rolling in the austenite phase
Microstructure
Thermodynamics
Crystallography
800°C
Predictions of secondary phases by 
simulation (JMatPro)
Microstructure: large prior austenite 
grains and fine martensite laths
Fine distribution of carbides (TaC) and nitrides (VN)
Yield strength
DBTT / USE
Creep
Conclusions:
TMT leads to a shift in mechanical and microstructural properties:
• Ausforming at 900°C is the most effective way to refine the microstructure and distribution of the secondary phases.
• The high solution treatment at 1250°C leads to a full dissolution of all carbo‐nitrides.
• PAG size is very large due to dissolution of TaC
• Creep Tests are still running, preliminary results look very promising.
... mehr
KIT – University of the State of Baden-Wuerttemberg and
National Research Center of the Helmholtz Association
This work has been carried out within the framework of the EUROfusion Consortium
and has received funding from the Euratom research and training Programme 20142018 und grant agreement No 633053. The views and opinions expressed herein do
not necessarily reflect those of the European Commission. The authors are grateful
to all their colleagues at the Karlsruhe Institute of Technology.