基于矩形线圈水平分量磁场分析的脉冲漏磁检测研究

针对铁磁性材料金属的缺陷检测,提出了一种基于矩形线圈水平分量磁场分析的检测方法.在涡流和漏磁理论基础上,建立了矩形激励线圈检测仿真模型.仿真表明:矩形线圈的下方水平磁场平整,当线圈轴线与缺陷方向垂直时,线圈底部水平分量的磁场与缺陷形成90°夹角.在铁磁性金属材料中,铁和空气介质处相对磁导率不一致导致磁场的偏转,产生了较强的漏磁场.在非铁磁性金属中,磁感线在缺陷处分布较为平滑,并不存在漏磁现象.搭建了检测平台,并分别在缺陷边缘和上部放置了Hall和GMR巨磁阻传感器进行检测.实验结果表明:在铁板表面,z分量磁场是涡流场和漏磁场的矢量叠加,磁场强,但与缺陷深度并没有线性关系;x分量磁场是单一的漏磁场,与缺陷深度存在线性关系,可以对缺陷进行定量分析.

Investigation of pulsed magnetic flux leakage testing based on horizontal magnetic field analysis of rectangular coil

Aiming at the problem that detection of ferromagnetic material,the method of pulsed magnetic flux leak testing based on horizontal magnetic flux of rectangular coil was proposed. The finite element simulation model with rectangular coil was established on the base of the theoretical analysis of eddy current and magnetic flux leakage. The simulation resultshave showed that when the axis of rectangular coil is perpendicular to the direction of crack, the horizontal magnetic flux line deflect on the junction of iron and air. At the situation,magnetic flux leakage filed is formed. According to the results of finite element simulation,the specimen and sensors are manufactured. The ex-perimental result indicates that z direction magnetic flux is constituted with EC magnetic filedand leakage filed with-out linear relation;x direction magnetic flux has a linear relation with the depth of crack and can be a characteristic quantity on the detection of ferromagnetic material.