Institute of Fundamental Technological Research

The paper deals with the application of lock-in active infrared thermography as one of the non-contact and non-destructive techniques used for estimating defect depth. Preliminary research was done by testing a specimen made of austenitic steel plate with artificially created defects, i.e. flat-bottom holes. The obtained dependence between defect depth and phase shift was presented for different frequencies of “thermal waves” generated inside the sample. The experiment was carried out to determine the application of the lock-in thermography approach in testing materials with a high thermal diffusivity.

non-destructive testing, lock-in thermography, defect depth, phase shift, thermal diffusivity