TPT March 2018

T E CHNOLOG Y

Detection of critical surface defects in hot rolled long metal products and tubes

that are detected by ET. However, this also leads to another problem: a very precise synchronisation between the image and the signal is required at high instant speeds. With recent advances in image capture technologies and ISEND ET solutions this is now possible. The acquisition rates of ISEND’s HOTdiscover family of solutions, which is a technology for obtaining and synchronising the images, have allowed the creation of a new system called EDDYeyes that combines both technologies. This allows the user to take real-time images of every defect detected by eddy current, which offers invaluable detection information for the user.

moves to the identification of the types of defects, with the aim of avoiding critical flaws for specific customers. The ideal solution is correlating and characterising the different types of defects depending on the electromagnetic signal they produce, but this comes with an even bigger problem: it is extremely difficult to physically locate a defect in a coil of several kilometres, then measure its position accurately and locate the signal it produced in the detector. The easier way, and probably the only possible way with current technology, is to analyse the coil rings that are visible and that always coincide with the tail of the same. But the tail is a special area in which the behaviour of the detectors and the material is different from the rest of the coil. Trying to characterise defects in tails can have disappointing results. There is another way to address this problem: taking pictures of the defects

FOR a long time non-destructive testing (NDT) methods have been used for the detection of surface defects in hot rolled long products. It is a complex discipline due to production conditions such as speed, temperature and environmental contamination. Eddy current testing (ET) is reliable, accurate and widely used for the task. However it has a problem: the electromagnetic signals are difficult to understand, and it is difficult to create virtual images. Therefore its main use is orientated to a classification of the coils by statistical criteria based on a combination of measurable elements such as the number of defects per unit of length or the amplitude of the signals they produce (usually related to the severity of the defects). Once the clients have reached an optimum sorting procedure, their priority

ISEND SA – Spain Email: contact@isend.es Website: www.isend.es

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LANG TUBE TEC GmbH, Industriestr. 6, D-64653 Lorsch / Germany

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MARCH 2018