Investigation the effect of heat treatment on brass defect measurement using Eddy Current Testing

Abstract

Eddy current technology has been used as a non-destructive method of measuring material properties for many years. Most applications of the eddy current technique lie in locating surface or subsurface flaws and evaluating material characteristics. This paper investigated the effect of heated brass material on material conductivity and defect measurement using eddy current testing (ECT). The ECT signal is compared and analyses in order study the effect of annealing on electrical properties of brass material. Brass block sample is designed and artificial defect with depth of 0.5mm 1.00mm and 2.00mm fabricated using Electrical discharge machining (EDM) machine. Industrial standard ECT set is used inspect the conductivity depth of defect brass sample before and after annealing process. Different frequency of ECT coil excitation are applied in order to determine the suitable ECT inspection frequency on brass material. The experimental results show the heat treatment decrease the conductivity of brass material. Due the changes of electrical properties on heated brass, the measurement of depth defect affected the value of amplitude ECT signal. Where the heated brass material reduced 10% IACS signal.