Multiparameter magnetomechanical NDE

We present a new approach to microstructural magnetic nondestructive evaluation (NDE) based on multiparameter measurements of magnetomechanical properties. A steel specimen was magnetized with a C-core using a triangular waveform of order 1 Hz in frequency. Hysteresis loops were obtained for five quantities: magnetoacoustic emission (MAE) and Barkhausen effect (BE) intensities, magnetic flux derivative, external magnetic field strength, and magnetostriction. The ability to extract the magnetic flux second derivative and the derivative of the magnetostriction permitted the investigation of several new interrelationships between MAE and other magnetic properties. Approximate coincidences were observed between MAE peak field position and peaks in magnetic flux second derivative and derivative of the magnetostriction. These effects are discussed and reproduced using existing magnetic modeling of MAE and corresponding modeling of flux density and magnetostriction.