Abstract
In the last few years, induction thermography has been established as a non-destructive testing method for localizing surface cracks in metals. The sample to be inspected is heated with a short induced electrical current pulse, and the infrared camera records—during and after the heating pulse—the temperature distribution at the surface. Transforming the temporal temperature development for each pixel to phase information makes not only highly reliable detection of the cracks possible but also allows an estimation of its depth. Finite element simulations were carried out to investigate how the phase contrast depends on parameters such as excitation frequency, pulse duration, material parameters, crack depth, and inclination angle of the crack. From these results, generalized functions for the dependency of the phase difference on all these parameters were derived. These functions can be used as an excellent guideline as to how measurement parameters should be optimized for a given material to be able to detect cracks and estimate their depth. Several experiments on different samples were also carried out, and the results compared with the simulations showed very good agreement.
Highlights
Induction heating is a well-known technique, as it is very efficient, fast, clean and accurately controlled [1]
During and after applying a short heating pulse, which is usually between 50 ms and 1 s, heat will be induced inside the material and an infrared camera records the temperature distribution
Evaluation of the temperature images and their temporal changes represents an excellent technique for crack detection, as it is a non-destructive, contact-free technique and can be very well fully automated using image processing methods
Summary
Induction heating is a well-known technique, as it is very efficient, fast, clean and accurately controlled [1]. Nowadays, it is used in the industry, and for domestic applications, as induction cookers, and for medical purposes, as hyperthermia therapy [1]. During and after applying a short heating pulse, which is usually between 50 ms and 1 s, heat will be induced inside the material and an infrared camera records the temperature distribution. In the last few years, several investigations have been published by different groups proving the applicability of this method. The first industrial application was reported around 30 years ago [2]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
