Hot wire inspection using eddy current

The configurations of the ECT (Eddy Current Tester) system in hot-wire and rod line comprise a guiding device, a tester (Defectomat CS) and a very efficient computer system for data acquisition and processing. The difficulties due to lack of straightness and vibration when feeding wire to test coils have been solved with a guiding device designed by POSCO (Pohang Iron & Steel Co. Ltd). The data processor is designed to process an analog signal for the smallest evaluation units. In addition to assessing an individual defect with an eddy current signal, statistical considerations of the signal make it possible to detect periodically occurring flaws. The test results in the user monitor are represented by colored bars and those of the previous coils remain on the screen until the next coil has been completely tested, which makes it possible to identify quality trends by comparing the coils. After experimenting with a defected billet having artificial hole or broken roll, the ECT system is at use on the wire and rod line of POSCO.