基于脉冲涡流(瞬变电磁)技术的带包覆层压力管道壁厚检测研究

Study on Wall Thickness Measurement of Pressure Pipe with Coated Layer Based on Pulse Eddy Current (Transient Electromagnetic Method) Technology

采用脉冲涡流检测(瞬变电磁)技术对带包覆层的构件进行壁厚测量时,铝皮保护层会对脉冲涡流信号产生一定影响。以单对数坐标系中晚期信号直线段斜率作为表征被测构件壁厚的特征值,通过试验数据获得壁厚与特征值的拟合关系式。结果表明:铝皮保护层对测量结果的影响与被测构件的壁厚有很大关系,壁厚越薄,受影响越大。当壁厚大于6 mm时,铝皮保护层对测量结果影响较小;铝皮保护层越厚,对薄壁构件的影响越大,测量误差越大;当以单对数坐标系中晚期信号直线段斜率作为表征被测构件壁厚的特征值时,提离高度对测量结果影响不大。

When measuring the wall thickness of a component with a cladding layer by pulsed eddy current testing(transient electromagnetic method)technology, the aluminum sheet has some influence on the PEC signal. The late signal slope of the straight line in the mono-logarithmic coordinate system was used as the characteristic value of the wall thickness measurement. The fitting relationship between the wall thickness and the characteristic value was obtained through the experimental data. The results show that the influence of aluminum sheet on the measurement results is closely related to the wall thickness of the component to be measured. The thinner the wall thickness is, the greater the influence is. When the wall thickness is greater than 6 mm, the influence of aluminum sheet is small. The thicker the aluminum sheet, the greater the influence on the thin-wall thickness of the measured component, the greater the measurement error.When the late signal slope is used as the characteristic value of the wall thickness, the lift-off has little effect on the measurement results.