Non-Destructive Testing with Magnetic Sensor Using Rotational Magnetic Flux

This paper presents a new nondestructive testing (NDT) method which utilizes rotational magnetic flux. In conventional eddy current NDT, the magnetic sensor is driven by an ac or dc current. Consequently, the magnetic field generated in the magnetic material is aligned in a single direction. However, in order to estimate the shape or position of an unknown defect, a two-dimensional alternating magnetic flux density vector is necessary. An NDT system utilizing rotational magnetic flux is proposed. In this system, the magnitude and phase value are measured and used to obtain information about the defect.