Due to beneficial mechanical properties, cast manganese (Mn13) steel is used for premium grade railway turnout frogs worldwide. However, its coarse-grain structure makes common non-destructive testing (NDT) methods for defect detection used in this industry very difficult to apply. Inductive thermography is a NDT method well suited for this problem.
Scanning inductive thermography is used to localise surface defects on the running surfaces of turnout frogs. Once localised, we propose additional static measurements to characterise the detected surface defects with respect to crack length, depth and penetration angle. Simulations with ANSYS Multiphysics are conducted to study the influence of different crack geometries as well as the influence of different excitation parameters. Validation measurements on samples with defined crack geometries are conducted. The results of both, simulation and measurements on samples, are used to characterize surface defects on actual manganese turnout frogs.