Non-destructive magnetic adaptive testing of ferromagnetic materials

A simple way of measuring and processing of magnetic parameters, intended to optimize their ability to reflect mechanical and structural alterations of ferromagnetic materials is described here. The method is adaptive with respect to the investigated material and to the investigated structural alterations of the sample, as it always utilizes that particular range of the measured data, that is the most sensitive to the explored material and to its explored structural change. The optimum elements of the suitably defined matrices of the magnetic variables, based on the measurement of families of minor hysteresis loops, are more sensitive than any of the traditional parameters obtained from the saturation-to-saturation loop. In order to get the optimum elements, the samples do not have to be measured up to their saturation value, but to a pre-determined lower magnetization value only. The method is illustrated on magnetic reflection of plastic deformation of a construction steel sample. (C) 2003 Elsevier B.V. All rights reserved.