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Electromagnetic Testing - Eddy Current Testing Applications Chapter 5 & 6

Eddy Current Chapter 5 and 6

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5.1.5.10 Sorting materials by magnetic permeability<br />

In eddy current testing the test coil is sensitive to many test parameters,<br />

including magnetic permeability. Due to the amplification effect caused by<br />

magnetic permeability, measurement of permeability and high levels is<br />

generally not possible. However many paramagnetic alloys can exhibit<br />

permeability properties and almost any non-magnetic alloy can pick up<br />

magnetic inclusions or contamination during manufacture or service. At<br />

normal eddy current test frequencies magnetic indications will often appear<br />

similar to discontinuities. Magnetic indications can be distinguished from<br />

discontinuities by re-testing at a reduced test frequency.<br />

Keywords:<br />

Magnetic indications can be distinguished from discontinuities by re-testing at<br />

a reduced test frequency. (why?)<br />

Charlie Chong/ Fion Zhang

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