基于脉冲漏磁的表面缺陷判别

Discrimination of surface defects based on pulsed magnetic flux leakage

考虑到涡流效应对脉冲漏磁信号的影响,仿真了不同激励电压、不同磁芯相对磁导率、不同缺陷深度和埋藏深度下的缺陷脉冲漏磁信号,发现了检测信号的过冲和波动现象。基于此现象提出了两种近表面或深埋藏缺陷的判别方法,即基于过冲及波动现象的方法以及基于导数极值的方法。最后通过试验验证了上述方法的可行性。

In this paper,the effect of eddy current on pulse magnetic flux leakage(PMFL) signals is considered.The PMFL signals of defects under different excitation voltages,relative permeability of the magnetic core,defect depth and burial depth are simulated,and the overshoot and fluctuation phenomena of the defect signals are found.Based on the phenomena,two methods for discrimination of near surface and deep buried efects are proposed,the overshoot and fluctuation phenomena method and the extreme value of the derivative signals method.Finally,the feasibility of the above methods is verified by experiments.