Induction thermography: Principle, applications and first steps towards standardization

A survey on theory, characteristic quantities and the experimental technique of induction thermography is given. The induction frequencies range from 1500Hz to 52MHz. Induction thermography is used for surface defect detection in forged parts of ferromagnetic steel. The sensitivity for crack detection is comparable to magnetic particle inspection. Hidden defects in steel can be detected, if necessary by lowering the induction frequency. Defects of fibres were detected in carbon fibre reinforced polymer. In silicon solar cells, cracks were detected with good contrast. A new field is crack detection in railway components like rails and wheels.