基于信号斜率的铁磁材料脉冲涡流测厚研究.pdfVIP

学兔兔 第32醛 第10期 仪 器 仪 表 学 报 Wo1 32 IJ_l0 201 1 10门 Chinese Journal of Scientific[nstrument 0ct．20l1 基于信号斜率的铁磁材料脉冲涡流测厚研究 柯 海，徐志远，黄 琛，武新军 (华巾科技大学制造装备数字化国家_T程研究中心 武汉 430074) 摘 要：以厚壁铁磁性材料为对象，研究r基于晚期信号斜率的脉冲涡流测厚方法。首先分析_r铁磁性材料脉冲涡流时域信 号的特点，得出峰值、峰值时间、过零点、提离交叉点等特征量难以适用的结论。然后将感应电压信号从直角坐标系转换剑单对 数坐标系，针对单对数坐标系下晚期信号趋于直线且直线斜率与材料厚度一一对应的特征，提出以信号斜率为特 量的脉冲涡 流信号分析方法。最后开发丫实验系统，运用该方法在16MnR阶梯钢板上进行了实际测量。实验结果表明，该方法能有效地 Ⅲ于铁磁性材料的厚度检测，检测范围大，壁厚误差小于5％，日 受提离影响。 关键词：脉冲涡流；铁磁性材料；厚度测量 中图分类号：TG115．28 文献标识码：A 国家标准学科分类代码：430．40 Research on thickness measurement of ferromagnetic materials using pulsed eddy current based on signal slopes Ke Hai，Xu Zhiyuan，Huang Chen，Wu Xinjun (State Engineering Research Center of Manufacturing Equipment Digitization， Huazhong University of Science and Technology，Wuhan 430074，China) Abstract：Thickness measurement of thick—wall ferromagnetic materials using pulsed eddy current(PEC)technology was studied based on the feature of late signal slopes．At first，time domain features of the ferromagnetic material PEC signals are analyzed in time domain，which indicates that the common features such as peak value，time to peak value．time to zero crossing and point of lifI-off intersection are difficult to apply．So．we switch the Cartesian eoordi— nate system to the semi—logarithmic coordinate system；and use the characteristic that in the semi—logarithmic eoordi— nate system，the late signal tends to a straight line and the straight—line slope corresponds with the thickness ot‘the test specimen．A new feature based on the late si