Surface and interior crack of graphite electrode is one of the major factors caused breaking accident of the electrode in electrical furnace that uses graphite electrode. Therefore, the detection of the interior crack of graphite electrode has practical and important application value. Pulsed eddy-current method (PEC) is widely used to survey conductive anomaly or ore body buried underground in geophysical prospecting. We have an idea to use PEC in nondestructive testing of graphite electrode with micro cracks and verify the applicability through the numerical simulation and experimental method. We make a code for the simulation and imaging and a PEC device for testing graphite electrode. According to numerical simulation, PEC can discriminate the interior cracks which has depth of the cracks location less than 13 centimeters. The experimental result shows that the proposed method can be used to find out the geometrical state of surface and interior cracks of graphite electrode and finally, quantitatively evaluate the quality of it.
Jon et al. (Mon,) studied this question.