文档介绍：I 摘要电导率是金属材料的一个重要物理量,它与金属的纯度、合金成分、热处理状态、硬度以及温度等密切相关。由于涡流检测能对金属电导率有良好的反应, 故利用涡流导电仪测试金属的电导率,就能对金属成分,杂质含量、热处理状态等进行鉴别。这种测试方法在航空、电力、造船、石油化工等领域都有重要应用。但是,在应用涡流法测量金属电导率时,涡流传感器的提离信号是电导率测试的主要干扰信号。因此,如何抑制提离干扰信号以准确的测试电导率,以及高性能导电仪的研制一直是国内外涡流检测界的研究重点。本课题的研究内容是在对涡流提离效应进行理论分析的基础上,寻找一种简捷的提离效应抑制方法。从而研制出高性能的便携式数显涡流导电仪。论文首先阐述了涡流检测线圈阻抗分析的原理,指出影响线圈阻抗变化的各种因素。针对目前的两种硬件抑制提离的方法需要反复调整工作点,操作麻烦的缺点,提出了利用相位转换抑制提离的方法。基于该方法在导电仪样机的研制过程中,采用AT91RM9200微处理器对检测信号的幅值和相位进行采样,计算,查表等,获得试件的电导率数值。论文中分别对电导率测试仪整机的硬件、软件进行设计,并对整机进行组装调试。最后通过对各频率点下大量标准试块进行测试,得出该仪器能较为精确地测量出1~112%IACS内非铁磁性金属材料的电导率数值;并且验证了相位转换法能够较好地抑制提离效益对测量产生的影响。为进一步研制出智能化数显涡流导电仪的工作提供了良好的基础。关键词:提离效应, 无损检测, 导电仪 II ABSTRCT The conductivity, which is bound to metal purity, alloyingredients, heat treatment status, hardness and temperature, etc, isthe one of the most important physical property of metal materials. Because of the sound sensitivity of the eddy current test, the metal components, the content of impurity,the heat treatstatus, etc, can be distinguished by using this method, which has been widely adopted in many fields such as Aviation, Power System, Shipbuilding petroleum and chemical engineering. However, the problem of the lift-off effect is still the main interference in the process of the eddy current test. So how to restrain the lift-off effect for accurately measuring the Conductivity and, at last, making out the instrument with high quality has been paid attention in China and other countries. The aim of this project is to find out a simple method to restrain the lift-off effect and make out an intelligent device with high quality and digitalized displaying function. This will fill the vacant in the domain of NDT in China. The principle of impedanceanalysis on eddy current testing coil is firstly analyzed in this paper, which point out all kinds of factor which causes the change of coil impedance. Specially facing the ings, such as repeatedly adjusting working point plicatedly operating of the two methods for restrain