对钢轨裂纹进行高速漏磁巡检时，钢轨的磁化强度直接影响缺陷漏磁场的产生及检测灵敏度。研究了巡检速度、励磁激励和磁轭磁极距被测钢轨的距离(提离)三个因素对钢轨材料磁化强度的影响。通过分析缺陷漏磁检测信号的幅值、检测磁路空气隙处的磁场强度、钢轨材料的磁导率变化得出：巡检速度在2~55 m/s范围内时，巡检速度提高，有利于提高高速漏磁裂纹检测的灵敏度；同时，励磁激励电压增加和提离减小都将有利于钢轨材料的磁化强度，从而有利于提高高速漏磁裂纹检测的灵敏度。

The detection sensitivity and magnetic flux leakage are decided by the magnetization of rail for fast magnetic flux leakage testing. The main work of this thesis is to make sure how speed of detection, excitation and lift-off shall affect the magnetization of rail. The magnetic field intensity between rail and yoke , amplitude of magnetic flux leakage signals and alteration of rail’s magnetic permittivity are analyzed, and it is found that increment of speed of detection makes for detection sensitivity when the speed is from 2m/s to 55m/s. Meanwhile, increase of excitation and decrease of lift-off enhance magnetization of rail, which is propitious to detection sensitivity.