Ultrasonic method is the leading and the most multipurpose way of non-destructive testing of material and products.
Nordinkraft had successfully implemented non-contact way of excitation and receiving of ultrasonic vibrations based on electromagnetic-acoustic transformation.
EMAT sensor contains case with socket, inductive coil, protector, magnetic concentrator and permanent magnet; Alternative current feeds the inductive coil, as the result the coil starts to emit electromagnetic oscillations, which byturn induce eddy currents on the surface of the test object.
Eddy current interferes with permanent magnetic field and as a result ultrasonic vibration arises directly on the surface of test material. That vibration propagate in the test object, reflects from the walls or defects and returns to EMAT area. Ultrasonic vibration in permanent magnetic field generates electromagnetic waves, which receives by transducer’s coil. Thus, interaction of the EMAT and material surface is performed by means of electromagnetic effects. That allows making testing through the air or any other non-shielded gap. Thus the described device have huge concurrence advantages over classic thickness gauges.