Magnetic Flux Leakage Course of Inner Defects and Its Detectable Depth

Abstract As a promising non-destructive testing (NDT) method, magnetic flux leakage (MFL) has been widely used for steel structure inspection. However, MFL still faces great challenge to detect inner defects. Existing course researches mainly focus on surface-breaking defects while that of is overlooked. In the paper, investigated by building circuit models, performing numerical simulations, and conducting experiments. It found near-surface wall an enhancing effect due higher permeability than air. Further, high-sensitivity method consisting Helmholtz coil magnetization induction with high core proposed increase detectable depth Experimental results show buried up 80.0 mm can be detected, suggesting potential deeply-buried future in field NDT.