NDTnet 1998 Aug, Vol.3 No.8

Abstract

A method has been worked out for eddy current testing of surfaces and surface cracks or corrosion under dielectric or non-magnetic metal layer up to 10 mm. The method is based on excitation of eddy currents by a coil with U-type core and information reading by a sensitive gradientometric element located on a axis of symmetry of the core.

This enables to locate both small surface cracks from 0.1 mm deep and subsurface defects with one and the same eddy-current converter. This also allows to reveal corrosion between sheets while suppressing the influence of variation of clearance between them.

The developed method is used in eddy current defectoscopes used for detecting corrosion spots in the body of the plane through aluminium cover, cracks detecting in helicopter blades under dielectric covers up to 6 mm thick, in pipelines under protective covers up to 10 mm thick, etc.

High selective performance of the sensor enable to detect surface cracks in ferromagnetic and non-magnetic welded connections under rust or dirt layer without prior cleaning.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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