Development of NDT to detect corrosion in automobile tires

Abstract

In the present work, various induction thermographic techniques have been tested to detect corrosion traces over embedded steel wire in cooked rubber (simulating bead wires condition in automobile tires). Accordingly, samples have been created, and 3 types of induction coils have been used: Planar coil, Helmholtz coil and Tesla coil. Results showed that planar coil provided general distinguishment between corroded and pristine wire; however, it failed to show the location corrosion traces. Helmholtz failed to provide uniform heating maybe due to poor coils design. Finally, the Tesla coil showed the best performance in providing higher induction energy, more uniform heating, and more temperature difference between the pristine and corroded wire. However, results showed that using simple temperature analyzing algorithms cannot be relied upon to produce accurate results when in comes to located corrosion in metallic objects. We also showed that depending on the complexity of the object being analyzed, the in-house algorithm gave promising results at pinpointing areas where corrosion occurred. In general, the correlation coefficient was a good indicator of where corrosion might be present. However, the algorithm produced some false positives when the object's geometry became more complex, or some precipitate might have formed. Nonetheless, the algorithm was able to show where corrosion occurred in most cases. More studies must be conducted to better optimize the image processing step and the amount of data acquired.