4. Conclusions
The magnetic-stress coupling effect is one of the basic characters of ferromagnetic materials. Based on such an effect, various magnetic NDT techniques in assessing the stress status of ferro- magnetic structures have been developed, some of which have been successfully used in engineering. However, understanding of the
magnetic-stress coupling effect is incomplete due to the complexity of the magnetic-stress action and high-sensitivity to the material’s microstructure. Thus, the applications of the NDT techniques in industry still face considerable challenges. Further studies of the NDT techniques are desirable.
In this paper, the current physical models for magnetic-stress coupling are introduced, and three representative magnetic NDT techniques (MFL, MNB and MMM) are reviewed. The fundamental features, advantages, disadvantages and future work for these NDT techniques are summarized based on a literature review of more than one hundred references.
Acknowledgments
This work was funded by Natural Science Foundations of China (no. 11072027), and the Fundamental Research Funds for the Central Universities and Ministry of Education of the People’s Republic of China (NECT).