Monitoring the Microstructural Evolution in Spheroidized Steels by Magnetic Barkhausen Noise Measurements

On the shape of the magnetic Barkhausen noise profile for better revelation of the effect of microstructures on the magnetisation process in ferritic steels

“…Conventional techniques like in-situ metallographic inspection is more time consuming and also limited to surface inspection. Magnetic NDE methods such as magnetic hysteresis [1][2][3], Magnetic Barkhausen Noise (MBN) [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] and Acoustic Barkhausen Noise (ABN) [4][5][6][7][8][9][10][11][12][13] have been shown to have great potential for characterisation of microstructure and stresses in ferromagnetic steels. As a NDE method, the MBN technique is considered for several applications due to its high sensitivity and relative easiness for industrial application directly on mechanical components.…”

“…and hence, the MBN signal is sensitive to composition, microstructure, texture and stresses in the ferromagnetic material. Previous studies [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] have demonstrated the applicability of MBN technique for assessment of several material properties in a number of ferromagnetic alloys. It has been observed that the MBN signal strongly depends on the measurement parameters such as maximum magnetic field strength, sensitivity and frequency response of pick-up coil, analysing frequency range of the MBN signal etc., which widely vary for different MBN measurement systems used by various researchers.…”

“…It has been observed that the MBN signal strongly depends on the measurement parameters such as maximum magnetic field strength, sensitivity and frequency response of pick-up coil, analysing frequency range of the MBN signal etc., which widely vary for different MBN measurement systems used by various researchers. Some studies [9][10][11][12] used low frequency magnetic excitation whilst others have used high frequency magnetic excitation for MBN measurements [14][15][16][17][18][19][20]. Also, some researchers [5,6,12,[14][15][16]19,20] have studied the changes in material properties using only a single measurement parameter such as root mean square (rms) voltage, energy, pulse height etc.…”

“…Some studies [9][10][11][12] used low frequency magnetic excitation whilst others have used high frequency magnetic excitation for MBN measurements [14][15][16][17][18][19][20]. Also, some researchers [5,6,12,[14][15][16]19,20] have studied the changes in material properties using only a single measurement parameter such as root mean square (rms) voltage, energy, pulse height etc. while some researchers [3,[9][10][11]13] measured the envelope or rms voltage profile of the MBN signal for analysis.…”

Thermokinetic Modeling of Phase Transformation in the Laser Powder Deposition Process

“…(2) Two steps are considered for the tempering: [11,22] (a) formation of transition carbide (e-carbide) and ferrite that occurs during tempering up to 250°C; and (b) formation of cementite and ferrite that occurs from 250°C up to A c1 .…”