一种基于远场涡流的管道大面积缺陷定位检测方法

在管道大面积缺陷的远场涡流检测中,由于远场涡流信号两次穿透管壁,远场涡流检测信号会两次出现对应于缺陷的特征响应,第1次响应为峰值信号,第2次响应为伪峰信号。峰值信号可实现管道检测处缺陷的正确定位与定量,而伪峰信号会在管道检测处造成错误的缺陷评估。并且,伪峰信号因为缺陷的形状、大小以及检测线圈尺寸而各异,对于缺陷定位、定量分析的影响亦不同。为了去除伪峰信号,首先采用同轴双接收线圈来获取具有时移关系的2个涡流检测信号,并校正2个检测信号由于检测位置以及其他因素造成的差异;然后,采用维纳去卷积滤波器滤除噪声并移除伪峰信号;最后,通过基于远场涡流的双接收线圈检测仪器,测试具有缺陷的管道。测试结果表明,该方法可行,具有很好的实用性。

Location and inspection method for large area pipe defectbased on RFEC testing

In large area pipe defect detection based on remote field eddy current (RFEC), since remote field eddy current penetrates the pipe wall twice, one defect causes two feature responses; the first response is the peak signal and the second response is the spurious peak signal. The peak signal can be used to achieve right location and quantification of the pipe defect; however, the spurious peak signal leads to the wrong estimation of the defect. The spurious peak signal varies with the size and shape of the defect, as well as the size of the detection coil; and its effects on the location and quantitative analysis of the defect are different. In order to eliminate the spurious peak signal, the two coaxial receiving coils are applied to obtain two eddy current detection signals with time shifting feature and the difference of the two signals caused by the detection position and other factors is calibrated. Then, the Wiener deconvolution filter is applied to filter out the noise and remove the spurious peak signal. The double receiving coil detection device based on RFEC was used to detect the pipe with designed defect; test results show that the proposed method is feasible and has good practicability.