电磁超声扭转波检测钢管缺陷的实验研究

Experimental research on defect detection of steel pipe based on electromagnetic ultrasonic torsional wave

扭转模态T(0,1)超声导波具有无频散的特点,便于信号分析与处理。在分析电磁超声扭转波传感器换能原理的基础上,搭建了电磁超声扭转波钢管缺陷检测实验平台,采用350 kHz的T(0,1)模态导波,在Ф25 mm×2800 mm壁厚2.5 mm的钢管上检测出20%壁厚损失的周向平底刻槽与Ф5 mm通孔缺陷,检测信号的信噪比较高。实验结果表明:这种电磁超声扭转波方法可以应用于钢管缺陷检测。

The T（0,1）mode ultrasonic guided wave of torsional mode has a feature of no dispersion,which makes it convenient to analyze and process signals.On the basis of analyzing transducing principle of electromagnetic ultrasonic torsional wave transducer,a laboratory platform for steel pipe defects detection is built.The T（0,1） mode guided wave of 350 kHz is used to detect the circumferential flat base notch with 20 ％ wall thickness loss and the through-hole defect of Φ 5 mm in a 2.8 meter-long steel pipe of Φ 25 mm whose wall thickness is 2.5 mm,signal-to-noise of detecting signal is high.Experimental results show that the method of electromagnetic ultrasonic torsional wave can be used to detect steel pipe defects.