Flaw detection system for thin steel sheet by leakage magnetic flux method

摘要

The present invention relates to a defect inspection apparatus for a thin steel plate defect by a leakage magnetic flux method, and more particularly to a defect inspection apparatus for inspecting defects of a thin steel sheet by a leakage magnetic flux method using a magnetic sensor, A high-pass filter 13 for eliminating the influence of the induction magnetic field is connected to the magnetic sensor 11 via the amplifier 12 and the noise is suppressed by the high-pass filter 13, And the output unit 15 is connected to the amplifier 15 through the low-pass filter 14. The magnetic sensor unit can be constructed simply because it is not necessary to install a very complicated magnetic shielding structure around the sensor But it has advantages of excellent sensitivity and low price, and it is also advantageous to operate the device conveniently.