基于磁表征的铁磁性零件表/界面形性加工在线检测原理与方法

Presently, the difficulty to improve the quality of parts processing is partly due to the accuracy limitation of the non-destructive testing and the lack of effective online inspection of the surface topography and subsurface performance (ST&SP) of ferrous parts. By combining the theory of magnetic leakage/refraction, the theory of self-magnetic polarization and the theory of magnetic distortion/disturbance/transmission that appears at the interface of the medium, this paper plans to start from the further discuss and classify of the surface appearance and the pre-discover of its magnetic characterization, seeking to propose an enhanced magnetic characterization method based on local micro magnetization and a dot/line mode high resolution induction method, in order to reveal the magnetic generation mechanism and the magnetic characterization law of the ST&SP of ferrous parts, to build up a numerical evaluation system for its characterization testing, to build up a ST&SP magnetic characterization spectral, and to break through key technology and theory of high precision magnetic flux leakage testing. Furthermore, a novel online magnetic inspection principle and method for the ST&SP of ferrous parts is brought up with the establishment of a ST&SP magnetic characterization online inspection database to support the obtain high quality parts, to enrich key technology and theory of the high precision parts processing/manufacturing, and to further explore the magnetism physical behavior and its effect beyond the common complex physical behaviors (such as force, heat) during parts processing process.

针对目前因无损探伤精度有限而缺少零件表面形貌和表层性态（表/界面形性）加工在线检测环节而最终难以突破提升零件加工品质的现状，从漏磁探伤中铁磁性材料表面状况的细分与磁表征预发现入手，结合介质分界面的磁折射泄漏、介质自磁极化及磁畸变扰动传递等电磁学理论，采用局部微磁化增强磁表征场法和"点（线）"式高分辨率磁感应法，揭示铁磁性材料表/界面形性的磁生成机制与磁表征规律，并建立其磁数值化表征检测与评价体系，形成铁磁性材料表/界面形性的磁表征信息谱，以突破高精漏磁检测关键技术及理论，最后提出一种基于磁表征的铁磁性零件表/界面形性加工在线检测原理与方法，创建铁磁性零件表/界面形性加工在线检测磁表征数据库，为突破零件高精加工制造关键技术及理论提供支撑以获得高品质零件，也为进一步探索零件加工过程中除了常见的力、热等复杂物理行为之外的磁学物理行为及其作用做铺垫。

针对目前缺少零件表/界面形性加工在线检测这一环节而难以突破提升零件加工品质的现状，本项目首先铁磁性零件磁滋生源头、磁传递与最终呈现机制着手，获得其磁表征规律及磁生成机制的理论解释。开展了铁磁性材料疲劳与缺陷通电对比测试研究，通过对不同材料的电磁学仿真与模拟，揭示其疲劳及缺陷信号的生成机制，拓展了高精电磁传感与检测体系的应用范围。在对铁磁性材料磁成分进行了深入探索的基础上，发现并验证了磁场中剩余磁成分主要由体电流二次漏磁场以及体电流扰动量组成，前者信号为单峰凸起形波形，后者由于体电流旁绕远离缺陷造成电流密度的稀疏性而形成下降的凹陷信号特征；其次开展了铁磁性材料2D及3D表面检测识别的模拟仿真研究，针对铁磁性材料表面三维“谷”形和“峰”形表面形貌建立了相应的计算模型，揭示了铁磁性材料表/界面形性的磁表征规律，即“谷”形表面形貌上方由于正向磁折射泄漏而形成“正”向漏磁信号特征，而“峰”形表面形貌由于自磁化极性场而形成反向磁表征信号。同时对美国ASTM E570:2009及英国BS EN 10246-4:2000等标准试件中的缺陷提出了补充修正意见；再次，开展了不同磁化方向对铁磁性零件表/界面形性加工在线检测的影响研究，有效解决了单一磁化下的多类型缺陷并行检测难题。发明并提出一种基于多重漏磁检测信号特征值缺陷评价方法，实现了高精铁磁性零件在线加工过程中表/界面形性的定量化无损评估。针对在线检测过程中的干扰颤振信号，采用频谱分析等方法，识别表面形貌与表层性态的磁表征信息，结合非接触式传感方法、低通滤波、小波变换等信号处理手段有效消除了颤振干扰；最后，发明并设计了磁轭式局部微磁化增强磁表征场与高分辨率磁感应技术，搭建了铁磁性零件加工在线检测实验装置，落实了铁磁性零件近表空域内非接触式加工在线传感方法并加以试验优化，有效解决了铁磁性零件在线加工过程中的远距离传感与检测难题。