Study on low frequency AC magnetic flux leakage detection for internal and external cracks of ferromagnetic structures

作者：Jiao Jingpin; Chang Yu; Li Guanghai; He Cunfu; Wu Bin

来源：Chinese Journal of Scientific Instrument, 2016, 37(8): 1808-1817.

• Ferromagnetic structures
• Magnetic flux leakage
• Magnetic flux leakage detection
• Magnetic flux leakage signal
• Magnetic-flux-leakage sensors
• Non destructive testing
• Phase parameters
• Pressure equipments

Based on the low frequency electromagnetic technology, the non-destructive testing of the internal and external surface of the ferromagnetic structures in the industrial pressure equipment is investigated. By analyzing the magnetic flux leakage signal and the amplitude and phase change of the magnetic flux leakage signal, a method for quantitatively characterizing the internal and external surface cracks of ferromagnetic structures is presented. Based on the low frequency magnetic flux leakage simulation model, the variation of the characteristic parameters of the magnetic flux leakage signal in different depths and different positions is studied. Furthermore, a single channel low frequency magnetic flux leakage sensor is developed and applied to detect the internal and external surface of the ferromagnetic structure with different depths and different positions of the artificial crack. Simulating and experimental results show that the amplitude is more sensitive to the depth of the upper surface crack, and the phase value is more sensitive to the depth of the lower surface crack, which provide technical support for the safe operation of the ferromagnetic structures of the industrial pressure equipment.

• 出版日期2016
• 单位北京大学