复杂型面轴承零件的高精漏磁探伤方法研究

The current magnetic flux leakage (MFL) testing method is far from meeting the requirement of the high-precision detection of micron-level defects for various types of bearing parts. However, in the study of improving the accuracy of MFL detection, it is found that the signal-to-noise ratio and detection ability of micron-level defects are seriously affected by the surface geometric features. Therefore, a high-precision MFL detection method based on the magnetic characterization of complex profiles is proposed. Firstly, on the premise of considering the surface roughness, surface texture and curvature characteristics of the complicated bearing surfaces, a multi-scale surface geometric feature and defect coupling MFL detection model suitable for electromagnetic analysis is established, and the coupling mechanism of the leakage magnetic field between the surface geometric features and the micron-level defects is studied. Secondly, the generating mechanism of the disturbing magnetic field caused by the surface geometric features is studied and the law of its effect on the MFL signal of defect is revealed, then, the quantification evaluation system of magnetic signal caused by the surface geometric features is built. Finally, according to the difference of multi-scale magnetic field signal characteristics caused by the surface geometric features and defects, a broad-spectrum MFL array sensing method with multiple spatial and temporal resolution is proposed. The micron-level defect signal is extracted from the multi-source fusion signal based on the complete magnetic signal characteristics of the complex profiles, which fundamentally improves the MFL detection accuracy for bearing parts with complex profiles. The successful implementation of this project will improve the performance of MFL detecting system and expand its application areas, which has prominent theoretical significance and application prospects.

现有漏磁探伤方法难以满足各类轴承零件微米级缺陷的高精探伤需求，而申请人在提升漏磁探伤精度的研究中发现，表面几何特征严重影响微米级缺陷的信号信噪比和检出能力。为此，本项目提出一种基于复杂型面磁表征的高精漏磁探伤方法。首先在考虑轴承复杂型面的表面粗糙度、表面纹理及曲率特征的前提下，建立具有电磁分析适用性的多尺度表面几何特征-缺陷耦合漏磁检测模型，研究表面几何特征与微米级缺陷的漏磁场耦合机制；其次揭示表面几何特征的扰动磁场生成机理及其对缺陷漏磁检测信号的影响规律，构建表面几何特征的磁信号量化评价体系；最后针对表面几何特征和缺陷的多尺度磁场信号特征差异，提出具有时空多重分辨力的漏磁广谱阵列传感方法，基于表面完整磁表征信号特征实现多源融合信号下的微米级缺陷信号提取，从根本上提升复杂型面轴承零件的漏磁探伤精度。本项目的成功实施将会提升漏磁探伤系统性能并拓展其应用范围，具有重要的理论意义和应用价值。

常规漏磁探伤方法难以满足轴承零件微米级缺陷的高精探伤需求，在提升漏磁探伤精度的研究中发现，表面几何特征严重影响微米级缺陷的信号信噪比和检出能力。为此，本项目提出一种复杂型面轴承零件的高精漏磁探伤方法。首先考虑了复杂型面轴承表面形貌特征、缺陷特征等影响因素，建立了具有电磁分析适用性的多尺度表面形貌-缺陷耦合漏磁检测模型，基于磁折射原理和电磁场边界条件等电磁基础理论，研究了表面形貌与微米级缺陷的漏磁场的耦合机制，揭示了表面形貌特征参数对缺陷漏磁检测信号的影响规律；其次，考虑不同轴承曲面对应的曲率变化、缺陷大小及走向等影响因素，对不同曲率特征与工件内磁场分布特征之间的影响规律进行了仿真和理论分析，研究了不同位置处微米级缺陷漏磁场信号的差异，揭示了曲率特征、缺陷位置处的局部磁化强度及缺陷漏磁场信号之间的影响规律及对应关系，为提高不同曲率处裂纹信号的一致性，对磁化器进行了优化设计，并且提出了基于轴承表面几何参数的缺陷漏磁信号处理及补偿方法，将不同位置处相同大小的裂纹漏磁信号一致性由20.74%提升到了91.21%；最后，从裂纹漏磁场信号的时间域及空间域分布角度入手，结合表面形貌引起的原生漏磁场信号、曲率特征引起的工件内部磁场差异和缺陷漏磁场信号特征之间的关联关系，基于裂纹漏磁信号的传感机制，研究了传统磁传感器与工件内外表面的接触及提离特点，为增强漏磁探头对微裂纹的检测能力，基于磁头结构特征及原理提出了一种基于测量回路的零提离漏磁检测传感原理，发明了具有多重分辨力的阵列广谱传感器，形成了多尺度表面几何特征-缺陷漏磁场信号的漏磁传感方法，为单一漏磁测头实现对跨尺度缺陷的检测提供了解决方案，既保证10um×10um微裂纹可被检出，同时可以保证大缺陷也可以被检出，并结合基于轴承表面结构特征的多源信号补偿方法，从根本上提升了轴承零件的漏磁探伤精度，对于提升漏磁探伤系统性能并拓展其应用领域，具有重要的理论意义和应用价值。