non destructive services
eddy-current testing
Eddy-current testing uses electromagnetic induction to detect flaws in conductive materials. There are several limitations, among them: only conductive materials can be tested, the surface of the material must be accessible, the finish of the material may cause bad readings, the depth of penetration into the material is limited, and flaws that lie parallel to the probe may be undetectable.
In a standard eddy current testing a circular coil carrying current is placed in proximity to the test specimen. The alternating current in the coil generates changing magnetic field which interacts with test specimen and generates eddy currents. Variations in the phase and magnitude of these eddy currents can be monitored using a second 'search' coil, or by measuring changes to the current flowing in the primary 'excitation' coil. Variations in the electrical conductivity or magnetic permeability of the test object, or the presence of any flaws, will cause a change in eddy current flow and a corresponding change in the phase and amplitude of the measured current. This is the basis of standard eddy current inspection, the most widely used eddy current technique.
However, eddy-current testing can detect very small cracks in or near the surface of the material, the surfaces need minimal preparation, and physically complex geometries can be investigated. It is also useful for making electrical conductivity and coating thickness measurements.
The testing devices are portable, provide immediate feedback, and do not need to contact the item in question.
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news at wis
WIS have implemented and are now accredited to the following: EN ISO 9001:2015, EN ISO 14001:2015 and EN ISO 45001:2018.
WIS have attended courses and examinations at QSA-Global in Houston, Texas and now have technicians trained and qualified in Servicing & Maintenance of the QSA-Global equipment. WIS also have technicians trained and qualified in Source Retrieval, this entailed the actual retrieval of a live source, which other companies providing this service do not carry out. WIS intend to roll out these services to NDT Contractors nationwide.