Improvement of RAFM steels through thermo-mechanical treatments

*contact: Jan Hoffmann E‐Mail: [email protected] 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. 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