Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Non-destructive electromagnetic test for detecting discontinuities in steels
Submission Author:
Edgard Silva , PB
Co-Authors:
Edgard Silva, Carlos Eduardo Bezerra Lopes, Francisco Eduardo Mendes da Silva, Ibernon Neto, Amanda Medeiros, Louise Gomes de Lima, Josinaldo Leite
Presenter: Edgard Silva
doi://10.26678/ABCM.COBEM2021.COB2021-1384
Abstract
Electromagnetic tests based on the interaction between magnetic flux density and material have been used to monitor the formation of microstructures that may compromise the mechanical properties and resistance to corrosion of materials. Among these we have those based on Magnetic Barkhausen noise and magnetic permeability in the region of reversibility of the movement of the magnetic domains walls. The latter has been applied to detect phases harmful to the toughness of stainless steels and the presence of magnetic anisotropy in materials with the presence of the ferrite phase. However, these tests have been used to detect cracks. These are physical interruptions caused by discontinuities or the presence of a second material such as gas or inclusion. In the present work, an electromagnetic test based on measurements of magnetic permeability and simulations by the Finite Element Method are used to detect the presence of discontinuities in a SAE 1045 steel. Discontinuities with 2 mm, 4 mm and 6 mm in diameter are analyzed and compared with condition without the presence of these. The Finite Element Method is used to show by simulation the possibility of detection by the configuration of the experimental bench used. An experimental configuration where the sample was positioned between a Hall effect sensor and a solenoid was used. Different intensities of magnetic fields until sensor saturation were applied to the solenoid in order to detect what best detected the presence of discontinuities. The simulation by the Finite Element Method was important to show the need for the positioning of a magnetic flux concentrator next to the Hall effect sensors for the concentration of the magnetic flux. The results show that the presence of discontinuity reduces the permeability of the material and shifts the magnetization curve to lower values of magnetic flux density. Magnetic field strength values applied close to sensor saturation showed better results. The electromagnetic test showed to be able to detect the discontinuity of 2 mm, which according to the quantity and concentrations are critical in structures of the oil and gas sector.
Keywords
discontinuities, Electromagnetic tests, Finite Element Method, permeability
