Nondestructive Testing for Shallow Defect of Ferromagnetic Objects Based on Magnetic Probe Structure

The magnetic flux leakage (MFL) technology is one of the most widely used electromagnetic nondestructive testing techniques. To magnetize the detected object near to saturated flux density, the excitation mechanism is heavy and large in the MFL technology. A simple and portable magnetic detector device for shallow defect of ferromagnetic objects based on the magnetic probe structure is designed in this paper. The proposed magnetic detector is very light, cheap, and easy to design and manufacture. The magnetic detector can make the qualitative and quantitative evaluation for shallow defect of ferromagnetic objects. In steel ribbon test, the maximum relative error of quantitative test results is less than 5% by the proposed magnetic detector device. In this paper, the application of the magnetic detection method for wire rope is proposed. By the proposed method, qualitative and positional detection of the wire rope defects can be easily achieved.