Showing papers on "Eddy-current testing published in 1974"

Coil arrangement and circuit for eddy current testing

Abstract: An eddy current coil test arrangement comprises an excitation coil for producing over a portion of a workpiece to be tested for defects an alternating magnetic field which penetrates the workpiece in a direction perpendicular to the workpiece surface to cause eddy currents flowing parallel to the workpiece surface. A pair of sensing coils for detecting defects coupled electrically in opposition are disposed within the range of the magnetic field and have their axes oriented perpendicular to the direction of the alternating magnetic field. The spacing of the sensing coils along the direction of their coil axes is approximately twice the distance between the loci of the two maximum voltage signals occurring across the winding of one coil responsive to motion of the coil arrangement over the workpiece surface in the direction of the coil axes and passing over a defect extending transversely to the stated direction.

Sensitive eddy-current testing of tubes for defects on the inner and outer surfaces

Abstract: The eddy-current method is widely used for the non-destructive testing of tubes.1 This report describes the extensive progress achieved in the last few years. The author discusses examples of testing techniques for tubes for nuclear engineering where extreme sensitivity is of the utmost importance, although the principles are also applicable to all types of tubes.