电磁阻抗法检测钢轨踏面硬度中提离效应的研究

Study on lift-off effect in rail surface hardness testing by electromagnetic impedance method

电磁无损检测钢轨踏面硬度中 ,检测信号对提离效应极其敏感 ,所以必须对提离效应加以抑制。本文针对电磁法铁磁材料硬度无损检测中的提离效应问题 ,提出了利用阻抗法 ,根据差动探头散射阻抗解析模型 ,对阻抗平面利用计算机图像处理技术进行处理 ,从而抑制提离效应 ,提高阻抗法进行铁磁材料硬度检测的精度 ,并建立了用于钢轨踏面硬度无损检测的电磁场数学模型 。

Testing signal is very sensitive to the lift off effect in the hardness nondestructive testing of rail surface by electromagnetic method, so lift off effect must be restrained. Aiming at the lift off effect in hardness nondestructive testing of ferromagnetic materials, the paper presents impedance method and impedance plane computer image processing according to the analytical mathematics model of differential probe scatter impedance, which decreases the lift off effect and increases testing precision by the impedance method applying in the hardness testing of ferromagnetic materials. The paper has built the electromagnetic field mathematics model used in rail surface hardness nondestructive testing, and the quantitative hardness testing of rail surface has been realized.