IR thermographic detection and characterization of hidden corrosion in metals: General analysis

Principles of infrared thermographic non-destructive testing for determining hidden corrosion in metals are summarized and discussed. 1D, 2D and 3D heat conduction models are introduced to simulate thermal processes in corroded areas. In thick metals, the lateral heat dissipation is mainly responsible for significantly smoothing the temperature contrast curves. Modelling small-size corroded sites requires 3D numerical models. Numerous defects have been simulated and the inversion formulas for determining material loss have been modelled for both flash and square-pulse heating. It has been shown that corrosion characterization inaccuracy is lower than 20% in cases representing a practical interest.