针对穿过线圈式涡流探伤头、尾信号大的特点,通过对前置放大器的增益进行自动控制和改善带通滤波器的滤波性能,减小钢管头部不可探区的长度。将辊道电机驱动变频器频率调在45Hz上,对Ф168 mm、厚6mm的钢管进行探伤实验,可清晰地检测出距钢管头部103 mm处的凹坑。 Aiming at the characteristic of passing through the coil eddy current testing head and the large tail signal, the length of the unexploded area of ​​the steel pipe head can be reduced by automatically controlling the gain of the preamplifier and improving the filtering performance of the band-pass filter. The roller motor drive inverter frequency is adjusted to 45Hz, the Ф168 mm, 6mm thick steel tube flaw detection experiment can be clearly detected from the head of the pipe 103 mm at the pit.