Eddy Current Testing (ET)
Eddy Current testing uses electromagnetic induction to detect flaws in conductive materials. In a standard eddy current testing a circular coil carrying current is placed in proximity to the test specimen (electrically conductive). The alternating current in the coil generates changing magnetic field which interacts with test specimen and generates eddy current. 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 presense of any flaws, will cause a change in the eddy current and a corresponding change in the phase and anmplitude of the measured current. This is the basis of standard (flat coil) eddy current inspection, the most widely used eddy current technique.
This method can be used to detect surface cracks through non-metallic coatings up to 2 mm thick. Eddy current testing can also be specified for use with non-ferritic materials, for example in an application standard. The techniques can be applied to coated and uncoated objects during fabrication and in service, both onshore and offshore.
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.
7108 8th Street NW
Phone: (780) 449-5013
Fax: (780) 449-5036