The invention discloses a method for detecting
ferrous magnetic material thickness by utilizing electromagnetic
ultrasound, and is characterized in that a
magnet inside an electromagnetic
ultrasound transducer takes a U-shaped permanent
magnet, a coil takes a PCB double-layer coil that takes the shape of a Chinese character, 'Hui' and is positioned at an opening of the permanent
magnet, and an effective lead part of the coil is parallel to the direction of a bias
magnetic field. In thickness measurement, the electromagnetic
ultrasound transducer is positioned on a detected object, high-frequency electric sinusoidal
pulse current passes through the coil, according to the magnetostrictive effect, the detected object generates partial stretching deformation and oscillation, and consequently excites ultrasonic
transverse wave and leads the ultrasonic
transverse wave to spread downwards in a direction vertical to surfaces of the detected object. The ultrasonic wave is reflected by a lower surface of the detected object, and then the reflected wave is received by the coil. A received ultrasonic
signal is collected and input into a computer after being amplified. If the ultrasonic wave spreading velocity in the detected object is v, and the spreading time is t, then the thickness of the detected object d is equal to a half of v multiplied by t. The method for detecting
ferrous magnetic material thickness by realizing the thickness detection of
ferrous magnetic materials, has the non-contact and couplant-free advantages, and can be used in high-temperature environment and for detecting materials with rough surfaces.