Comparative study of the annealing effects on the coercive field of two Eurofer ferritic-martensitc steels

• Grant number: 10/51759-9
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2011
• End date: October 31, 2011
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Maria Jose Ramos Sandim
• Grantee: Maria Jose Ramos Sandim
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

The aim of this project is to investigate the annealing effects on the coercive field (Hc) of two Eurofer ferritic-martensitic steel (9%Cr). Those steels have been developed for applications at high temperatures as structural materials in an nuclear fusion reactor (ITER project). Two kinds of EUROFER steel will be investigated, with and without a fine dispersion of Y2O3 particles, named as ODS-EUROFER and EUROFER-97, respectively. Samples of EUROFER steel with 80 % reduction will be annealed (under vacuum) at several temperatures up to 1350°C, followed by air cooling Hysteresis loops of the samples will be taken at room temperature, with the applied magnetic field parallel to the rolling direction (RD). For some representative samples the hysteresis loops will be also taken with the applied field perpendicular to RD. The coercive field values of the samples will be taken from the hysteresis loops. The Hc behavior will be correlated to the micro structural changes of the material under annealing. A comparison between the results obtained for ODS-EUROFER and EUROFER-97 will be focused, aiming the better understanding of the Y-based particles effect on both coercive field and thermal stability of the material. The results of magnetic characterization will be compared to the ones obtained by conventional techniques of evaluation of recovery and recrystallization, like Vickers microhardness and scanning electron microscopy. (AU)