Investigation of Pulsed Eddy Current Testing of Flaws in Ferromagnetic and Non-ferromagnetic Metals

Aiming at detection of defects in ferromagnetic and non-ferromagnetic metals, the finite element models of circular probes with vacuum and non-vacuum shieldings were built. In the presence of flaws, distribution of eddy currents and magnetic field for two kinds of metal materials were simulated. The validity of simulation analysis was demonstrated by experimental results. The results show that the pulsed eddy current with vacuum magnetic shielding can improve effectively the sensitivity on surface defects of ferromagnetic metals. However, it is not obvious that it is incapable of improving the sensitivity of the non-ferromagnetic metal defects and internal defects of ferromagnetic metal defects.