Development of a magnetic NDE imaging system using magnetoresistive devices

A magnetic imaging system has been developed for non-destructive evaluation of structural and mechanical conditions of materials using magnetic hysteresis and Barkhausen effect (BE) measurements. The system can be used to measure magnetic properties while scanning the surface of a material, and to convert the data into an image showing variations in the material conditions from one location to another. An integrated sensor probe capable of measuring both magnetic hysteresis and BE signals was developed using magnetoresistive devices. The imaging system has been found useful in detecting surface and sub-surface notches as well as thickness variations in steel plates.