Magnetic Barkhausen Technique Applied to the Characterization of As-Cast Model Steels with Parametric Variation of Ni, Mn, Si and Cr Content

Abstract

The present work is aimed to investigate the capability and the optimisation of magnetic Barkhausen techniques to support the characterisation study of model steels. The task is within the frame of a project aimed to determine the role and influence of Cr, Ni, Mn and Si as alloying elements on the radiation stability of reactor pressure vessel steels. A large spectrum of ferritic steels with basic typical composition representative of WWER-1000 and PWR reactor pressure vessel materials were manufactured and different testing on miniaturised Charpy V-notch samples was performed. For the Magnetic Barkhausen Noise (MBN) measurements a sinusoidal exciting magnetic field with magnetising voltage of 10 Vpp was used, the applied magnetizing frequency being 10 Hz. The signal of the pick-up coil was processed by a 5 – 500 kHz band pass filter and the gain of amplification was set at 20. The root mean square values (RMS) of the noise signal were determined and were used to characterise the 12 model steels and to analyse the correlation with the available material's mechanical properties; ductile-to brittle transition temperature (DBTT) and hardness (HV10) values. The results are very promising and the next step will be to repeat the measurements after neutron irradiation of such model steels in the HFR-LYRA irradiation facility up to accumulated neutron fluence in the order of 1019 n.cm-2 and the further comparison of material properties before and after irradiation.JRC.F.4-Safety of future nuclear reactor