在裂纹漏磁检测中尤其是微裂纹的检测受多种因素影响, 其中被检测工件的表面粗糙度是主要因素。为探求表面粗糙度与裂纹检测灵敏度间的关系, 在表面粗糙度试块上刻有不同深度的人工裂纹并进行漏磁检测试验, 得出了不同深度裂纹的检测信号信噪比。结果表明, 信噪比随着表面粗糙度值的增大而减小, 表面粗糙度一定时, 深度小到一定程度的裂纹将不能被有效检出。最后, 以三角形锯齿状粗糙元模拟固体表面粗糙度模型中的上凸部分和下凹部分, 从磁折射的角度分析了粗糙表面场强分布规律, 通过仿真给出了粗糙表面裂纹的理论检测灵敏度。

In magnetic flux leakage testing (MFL), test result was affected by various factors. Surface roughness was the main factor influencing the sensitivity of detection. The aim of this paper is to analyze the effect of surface roughness on crack detection sensitivity by an experiment on surface roughness reference block with artificial groove injury in different depth, and to analyze detection results of different rough surface by comparing the SNR. The results showed that the SNR value decreased as the surface roughness increased, and a certain depth of the crack could not be clearly distinguished at a determined roughness, moreover, triangular serrated roughness elements were taken to simulate the convex portion and the concave portion in surface roughness model of solid, and analyzed distribution of magnetic field intensity from the perspective of the magnetic refraction, the simulation results gave a theoretical detection sensitivity of crack on rough surface.