Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Harmonic analysis of electromagnetic waves for detecting embrittlement microstructures in a duplex stainless steel
Submission Author:
Edgard Silva , PB
Co-Authors:
Edgard Silva, Augusto Sérgio Oliveira Sampaio, Louise Gomes de Lima, Amanda Medeiros, Suelen Lima de Carvalho, Josinaldo Leite, João Pereira Leite
Presenter: Edgard Silva
doi://10.26678/ABCM.COBEM2021.COB2021-1385
Abstract
The magnetic properties depend on several characteristics of the materials, such as chemical composition, microstructure, hardness, stress states, deformations and heat treatments. Electromagnetic waves traveling through ferromagnetic materials bring information about the microstructures present. These interfere with the amplitude of the harmonics of the applied wave. In the present work, the amplitude of the emitting wave harmonics is studied to accompany embrittlement phases in steels. To apply harmonic analysis to this type of study, a material was chosen in which the only transformation in the study temperature is the formation of a single precipitated phase with these characteristics. A duplex stainless steel was chosen for this study. SAF 2205 steel at a temperature of 475 oC is characterized by having its mechanical properties and corrosion resistance compromised, due to the formation of a nanometric phase called α`. Thus, any variation in the signal will be due to this. An electromagnetic test composed of an emitting coil and a Hall effect sensor, with samples positioned between them, was applied. Emitting waves of 5 Hz, 10 Hz, 15 Hz and amplitudes of 0.25 V, 0.5 V, 0.75 V, 1 V, 1.25 V, 1.5 V, 1.75 V, 2 V, 3 V, 5 V, 7 V and 9 V were used. The obtained signals were passed to the frequency domain by the application of the fast Fourier transform and the intensities of the first harmonic were analyzed. The amplitude of these was used to accompany the formation of embrittlement phase formed in a duplex stainless steel used in the oil and gas sector. The measurements obtained by the electromagnetic test were correlated with the hardening of the material and its ability to absorb energy by impact. The amplitude values of the harmonics show that they are able to detect the presence of the precipitates and that their presence reduces the amplitudes due to the blocking of the movement of the domain walls. These shows to have a direct behavior with the absorbed energy and inverse with the hardness.
Keywords
embrittlement phases, electromagnetic test, harmonic analysis, Hall effect sensor, duplex stainless steel
