Pulse eddy current method is a non-destructive electromagnetic technique that is used to identify surface and subsurface defects. In the pulse method, unlike the conventional vortex flow method, which uses alternating current, non-sinusoidal current is used and therefore it can penetrate the induced currents to greater depths and extract more information from the sample volume. In this research, using the design of a differential probe, this non-destructive technique has been used to detect changes in the thickness of 304L austenitic stainless steel. For this purpose, samples with thicknesses between 5 to 1 mm that were prepared with very high dimensional accuracy were tested. The designed differential probe consists of an excitation coil and two sensor coils embedded in the center of the excitation coil. The excitation coil receives the pulsed current from the power supply and induces it in the samples, and the two sensor coils record the induced waves. By examining the shape of the pulses received from different samples and measuring their height and damping time, a logical relationship between the thickness of the samples and the characteristics of the pulses can be considered. The results show the acceptable accuracy of the proposed method in determining the thickness of austenitic stainless steel parts.

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