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Ultrasonic examination of materials often requires knowledge of the material’s acoustic velocity. Acoustic velocity is a function of the temperature of the material and change in velocity with respect to temperature (dV/dT) is not the same for all materials. Several materials have been tested to assess their dV/dT. This paper describes the setup and approximate values obtained for dV/dT over a range of temperatures from 20°C to 70°C. In addition, results from several other sources have been added to a table of values with reference to the authors.

In this paper Induction Thermography is considered as a complementary and even as an alternate technique to the conventional non-destructive techniques of Magnetic Particle and Dye Penetrant Inspections, for the detection of surface defects in the mechanical maintenance arena. Experiments using Induction Thermography, on metallic electromagnetic specimens were performed, in the laboratory as well as on a 304L stainless steel pipe specimen, an HP turbine stud and a CV-joint obtained from the power plant. The results delineated the presence of cracks as a solid line with higher contrast compared to other areas of the specimens. The technique revealed defects that were also detected with the conventional NDT of MPI and DPI techniques within a short period of time, and may be considered as a preferable NDT technique for large surface inspections.