Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2018-08-15

Journal: IEEE SENSORS JOURNAL

Included Journals: SCIE

Volume: 18

Issue: 16

Page Number: 6540-6546

ISSN: 1530-437X

Key Words: Low frequency; saturation magnetization; internal defect detection

Abstract: A ferromagnetic material equipment internal defect detection system based on low-frequency (20-50 Hz) electromagnetic technique was proposed. Direct current magnetization was used to make the ferromagnetic material sample (20# steel for instance) be in a saturation magnetization state to decrease its permeability, which is beneficial for increasing the skin depth of the sample and strengthening the signal of the magnetic flux leakage. A low-frequency alternating current source was used to excite the spatial alternating electromagnetic field and a Hall sensor was used to collect the signal of the spatial magnetic field. Experimental results showed that the 6-mm buried depth internal defect with the sensitivity of 0.05 mm can be detected in the 12-mm thick 20# steel plate or pipeline, which is almost 1.5 times higher than that of the current similar sensors.