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TUBE PRODUCTS INTERNATIONAL JANUARY 2015
Detecting metallic inclusions and defects in copper tube
A frequent problem for copper tube producers is the presence of foreign metallic inclusions, which can lead to failures, particularly in fluid transmission applications. Magnetic Analysis Corp’s eddy current MultiMac® tester with an additional magnetic inclusion detector (MID) absolute channel provides a convenient, reliable solution that can detect inclusions as small as 3mg.
In many cases, the inclusion can come from the material itself, which may contain residual impurities from continuous casting. In other cases, such as finned tube, the inclusions develop during the manufacturing process, where small particles of metal such as tungsten can break off from fabricating tools and become imbedded in the OD or even through the wall.
The MID option uses principles of flux leakage technology. A magnetic dual-coil test sensor consisting of one primary winding, associated with a secondary arranged in differential mode, and one single absolute winding for detecting metallic inclusions, is used.
A stable DC magnetic field is created and, in its presence, a magnetic particle on or within the non-ferrous product passing through the test coil will distort this magnetic field. The distortion induces a signal that is detected by the MultiMac electronics, analyzed and displayed on the monitor.
Additional conditions that can be detected by the Multimac are surface defects on the ID and OD, splits, tears, pinholes, and other irregularities such as indication of a broken disc. Setups and test data can be stored, recalled, printed and transferred to customer networks.
Magnetic Analysis Corp – USA
info@mac-ndt.com
www.mac-ndt.com
