Use of pulse eddy current thermography on welded steel and additive-manufactured titanium

This paper introduces a new method combining eddy current (EC) with thermography and virtual wave processing (VW). EC is a preferred method for detecting top surface defects in metals. EC has certain limitations. Combining it with thermal imaging creates a pulse eddy current thermography (PECT) hybrid method. While the technical aspect of PECT has evolved with time, it has never become a primary NDE tool; interpretation is lagging. We introduce a new interpretation based directly on the governing differential equation of heat propagation. By using relationships between wave propagation and diffusive propagation, one can transform from diffusive propagation to wave propagation. Having wave-like behavior produces simple-to-interpret images and allows the use of advanced techniques developed for wave propagation. This paper uses PECT to detect defects in welded steel and additive-manufactured titanium. We demonstrate high-resolution and depth-determination capabilities not possible with conventional EC