交直流漏磁钢轨裂纹检测对比研究

Research on Comparison of DC MFL and AC MFL Detection for Track Surface Cracks

摘要: 我国铁路钢轨表面裂纹是钢轨损伤的主要缺陷形式。针对钢轨裂纹缺陷的特点，从电磁场基本理论出发，研究直流漏磁、交流漏磁检测原理，搭建检测系统平台。实验比较研究了两种技术分别在手推、电机驱动低速和电机驱动高速三种巡检情况下的漏磁信号。提出了通过计算检测系统对缺陷的分辨率，来精确比较两种方法检测信号的优劣。实验表明，手推式和速度低于2 m/s的电机驱动低速巡检条件下，两种方法都能全面检测出缺陷，但交流漏磁信号比直流漏磁信号分辨率更高，信号更稳定，检出效果更好。电机驱动速度大于2 m/s时以及高速条件下，直流漏磁比交流漏磁能更准确地检测出缺陷。结合两种方法的优势，可互补实现对钢轨不同巡检条件下的裂纹全面检测。

Abstract: The surface cracks are the main defects of rail track. Based on the characteristic and electromagnetic theories, the DC magnetic flux leakage (MFL) and AC MFL are studied. And the measurement system is built up. Experiments are applied to study the MFL signals of DC MFL and AC MFL technology with hand-move, low-speed and high-speed motor drive. The defects detection solutions are calculated to compare DC MFL and AC MFL accurately. The experiment results propose that these two technologies can detect the surface cracks with hand-move and low-speed (<2 m/s) motor drive. AC MFL has higher solutions, more stable signals and better results than those of DC MFL. When the rotation speed is more than 2 m/s, DC MFL is more accurate. Combining each other these two technologies can detect the rail track in different measurement conditions.