Design and assembly of an apparatus system based on the Villari effect for detecting stress concentration zone on ferromagnetic materials

  • Doan Thanh Dat
  • Le Thi Hong Giang
  • Nguyen Dinh Dung
  • Hoang Anh Tuan
  • Nguyen Thi Le Hien
Keywords: Magnetic field apparatus, stress concentration zone, integrity assessment, defect detection, self-magnetic flux leakage


This paper presents the study results on the fabrication of a structural integrity assessment apparatus by determining stress concentration zones in pressure pipeline and equipment. The apparatus uses a triaxial magnetic field sensor to measure magnetic field components in three axes Ox, Oy, and Oz, in the working range of the magnetic field from -300 µT to 300 µT. The investigation of the selfmagnetic leakage field by this apparatus in the API 5L steel specimens under tensile stress shows a high variation of the magnetic field at a steel elongation lower than 1 mm (corresponding to the elastic deformation state of the material). In the case of an artificial defect, the apparatus can detect a change in the magnetic field caused by stress concentration.


Ravi Prakash, Non-destructive testing techniques. New Age International Publishers, 2009.

J.P. Joule, “On the effects of magnetism upon the dimensions of iron and steel bars”, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, Vol. 30, No. 201, pp. 225 - 241, 1847. DOI: 10.1080/14786444708645682.

E. Villari, “Change of magnetization by tension and by electric current”, Annals of Physics and Chemistry, Vol. 126, pp. 87 - 122, 1865.

Punit Arora, P.K. Singh, V. Bhasin, K.K. Vaze, D.M. Pukazhendhi, P. Gandhi, and G. Raghava, “Fatigue crack growth behavior in pipes and elbows of carbon steel and stainless steel materials”, Procedia Engineering, Vol. 55, pp. 703 - 709, 2013. DOI: 10.1016/j.proeng.2013.03.318.

A.A. Dubov, “A study of metal properties using the method of magnetic memory”, Metal Science and Heat Treatment, Vol. 39, pp. 401 - 405, 1997. DOI: 10.1007/BF02469065.

Le Sun, Xin'en Liu, and Hongpan Niu, “A method for identifying geometrical defects and stress concentration zones in MMM technique”, NDT & E International, Vol. 107, 2019. DOI: 10.1016/j.ndteint.2019.102133.

Anatolii A. Dubov, Sergey Kolokolnikov, “Technical diagnostics of equipment and constructions with residual life assessment using the method of metal magnetic memory”, 17th World Conference on Nondestructive Testing, Shanghai, China, 25 - 28 October 2008.

M. Roskosz and P. Gawrilenko, “Analysis of changes in residual magnetic field in loaded notched samples”, NDT & E International, Vol. 41, No. 7, pp. 570 - 576, 2008. DOI: 10.1016/j.ndteint.2008.04.002.

Shi Changliang, Dong Shiyun, Xu Binshi, He Peng, “Stress concentration degree affects spontaneous magnetic signals of ferromagnetic steel under dynamic tension load”, NDT & E International, Vol. 43, No. 1, pp. 8 - 12, 2010. DOI: 10.1016/j.ndteint.2009.08.002.

Caoyuan Pang, Jianting Zhou, Ruiqiang Zhao, Hu Ma, and Yi Zhou, “Research on internal force detection method of steel bar in plastic and yielding stage based on metal magnetic memory”, Materials, Vol. 12, No. 7, 2019. DOI: 10.3390/ma12071167.

Guo Pengju, Chen Xuedong, Guan Weihe, Cheng Huayun, and Jiang Heng, “Effect of tensile stress on the variation of magnetic field of low-alloy steel”, Journal of Magnetism and Magnetic Materials, Vol. 323, No. 20, pp. 2474 - 2477, 2011. DOI: 10.1016/j.jmmm.2011.05.015.

Shangkun Ren and Xianzhi Ren, “Studies on law of stress-magnetization based on magnetic memory testing technique”, Journal of Magnetism and Magnetic Materials, Vol. 449 pp. 165 - 171, 2018. DOI: 10.1016/j.jmmm.2017.09.050.

Dong Lihong, Xu Binshi, Dong Shiyun, Chen Qunzhi, and Wang Dan, “Variation of stress-induced magnetic signals during tensile testing of ferromagnetic steels”, NDT & E International, Vol. 41, No. 3, pp. 184 - 189, 2008. DOI: 10.1016/j.ndteint.2007.10.003.

Stephen George Henry Staples, “Using magnetostriction and the Villari effect to detect anomalies in steel materials”, PhD Transfer Report, June 26, 2012.

Nguyễn Thị Lê Hiền, Đoàn Thành Đạt và Lê Thị Phương Nhung, “Sử dụng nguyên lý Villari và kỹ thuật nhớ từ trong kiểm tra vật liệu từ chịu lực”, Tạp chí Dầu khí, Số 8, trang 60 - 66, 2020.

How to Cite
Doan Thanh Dat, Le Thi Hong Giang, Nguyen Dinh Dung, Hoang Anh Tuan, & Nguyen Thi Le Hien. (2020). Design and assembly of an apparatus system based on the Villari effect for detecting stress concentration zone on ferromagnetic materials. Petrovietnam Journal, 10, 60 - 66.