Advanced methods based on active thermography for fast inspection of cast iron exhaust manifolds used in the automotive industry

This paper explores the application of vibrothermography with ultrasonic excitation for the detection and quantification of flaws in industrial cast iron components. The use of amplitude modulated ultrasonic heat generation allowed selective response of defected area, since the defect itself is turned into a local thermal wave emitter. Due to the very fast cycle time (< 30 s/part), the method could potentially be applied for 100% quality control of cast parts. After a brief description of the measurement technique and experimental setup used to carry out the tests, main results and discussion are reported. Most emphasis has been addressed to assess the influence of different operative parameters on defect’s detection capability as well as accurate sizing of the discontinuity.