A Thermographic Method to Evaluate Different Processes Effects on Magnetic Steels

Ferromagnetic materials may be affected by the presence of local losses due to defects or magnetic anomalies caused by machining processes. To highlight such anomalies is absolutely not easy; a non invasive thermographic method has been refined to allow a proper comparison of different machining processes impact on the iron losses. Specimens obtained with punching, wire erosion and laser cut have been analyzed by means of a high speed IR camera when subjected to alternate magnetization at different frequencies. The possibility to point out localized anomalies should be exploited to foresee and avoid electrical machines core faults.