Dedicated Eddy Current Testing Transducer Developed

Eddy current testing (ET) is widely applied in various industrial sections for its unique advantages such as easy coupling, speediness, and low cost. However, due to the skin effect during eddy current testing, it is very difficult to detect deep flaws in a conductor through the change of the eddy current. Therefore, the researches on the enhancement of eddy current penetration depth under certain detection sensitivity condition are of great significance, especially the development of high performance eddy current testing probe is most important. In order to meet the requirement of non-destructive evaluation on welding depth detection of certain specific electron-beam- welded parts, the development of special high-performance eddy current testing probe was conducted in this thesis.In this paper, the factors which affected the performance of eddy current testing probe were analyzed firstly. The results indicated that the impedance change of probe was influenced by coil parameters, distance between coil and work piece surface, excitation frequency and work piece conductivity, magnetic permeability, defects, work piece geometry shape. According to the testing requirements of the specific components and the rule how various factors influence probe performance, optimizations of probe inspirit and induction way, coil connection methods and magnetic core, electromagnetism shield, coil size and the number of windings were performed, and a special-purpose eddy current testing probe was designed. Moreover, the main parameters of the probe were theoretically calculated.According to the optimized result, the author designed outer covering, coil frame, magnetic core for the probe and eddy current testing specimens. The coil intertwist, probe assembly and product seals technics which affect the probe quality were strictly controlled, and the manufacture experience of eddy current testing probe was gained primarily. Moreover, the main parameters of the eddy current testing probe were optimized by a group of orthogonal experiments, which further enhance its performance.Comparison experiments between the homemade probe and the purchased one were carried out with the test specimens respectively. The results showed that the homemade eddy current testing probe was better, which surpassed the purchased one in detection sensitivity and detection depth. Finally, the relationship between defect depth and eddy current testing signal phase was established through experiments. It tallied with the theoretically linear relationship, and was confirmed by experiments.The homemade eddy current testing probe is prominent comparison with similar...