Residual Magnetic Field Testing System with Tunneling Magneto-Resistive Arrays for Crack Inspection in Ferromagnetic Pipes

• Published in: Sensors (Basel, Switzerland) Vol. 24; no. 11; p. 3259
• Main Authors: Zhao, Shuxiang, Gao, Junqi, Chen, Jiamin, Pan, Lindong
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.05.2024; MDPI
• Subjects: Analysis; Carbon steel; crack detection; Cracks; Defects; ferromagnetic pipes; Ferromagnetism; Field study; Magnetic fields; magnetization; Magnets, Permanent; residual magnetic field; Sensors; Simulation methods; Stainless steel; Steel pipes; tunneling magneto-resistive (TMR); China; residual magnetic field; tunneling magneto-resistive (TMR); magnetization; crack detection; ferromagnetic pipes
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s24113259

Ferromagnetic pipes are widely used in the oil and gas industry. They are subject to cracks due to corrosion, pressure, and fatigue. It is significant to detect cracks for the safety of pipes. A residual magnetic field testing (RMFT) system is developed for crack detection in ferromagnetic pipes. Based on this background, a detection probe based on an array of tunneling magneto-resistive (TMR) sensors and permanent magnets is exploited. The probe is able to partially magnetize the pipe wall and collect magnetic signals simultaneously. First, a theoretical analysis of RMFT is presented. The physics principle of RMFT is introduced, and a finite element model is built. In the finite element simulations, the effects of the crack length and depth on the RMFT signal are analyzed, and the signal characteristics are selected to represent the crack size. Next, the validated experiments are conducted to demonstrate the feasibility of the proposed RMFT method in this paper.