Magnetic Nondestructive Inspection of Retained Austenite in Cast Iron

Since the cast iron is used for the parts of various heavy machines, the hardness of it should be high. The hardness is rapidly reduced by the appearance of the retained austenite in the cast iron. Therefore, the inspection of volume fraction of retained austenite in the cast iron is important. The B-H curve and the conductivity of the cast iron containing the austenite are different from those of the normal cast iron. Then, the detection of retained austenite is possible by measuring the change of electromagnetic properties using an electromagnetic inspection method. In this paper, the electromagnetic inspection technique of retained austenite in the cast iron is examined using 3-D edge-based hexahedral nonlinear FEM (finite element method). The possibility of detecting the retained austenite using the proposed inspection method is illustrated. In addition, the experimental verification is also carried out