Eddy current testing - ET
The eddy current testing - ET uses electromagnetic induction to detect discontinuities in conductive materials. The alternating magnetic field of the coil acts on the object under test to induce the alternating voltage. The conductive object is a closed current conductor and therefore circular, eddy currents. The eddy currents form their own magnetic field, which has the opposite phase as the exciting field. Thus, the drive field is weakened, and the resulting field is given by the vector sum of the two fields. Discontinuities in the article reduces the electrical conductivity of the material and thus also the density of the eddy current. The amplitude and phase of this resulting pole are the bearers of the subject status information. The change in the flow of the eddy current and the corresponding change of phase and amplitude is compared with the known values.
The eddy current testing method can detect very small cracks at the surface or near the surface of the material, the test surfaces require minimal preparation. The most advantageous method of the eddy current is that it can be used to determine surface flaws on a painted, insulated, or coated surface. The detection of flaws through this method is commonly used in the aeronautical industry, crane control, the cement industry, and other industries where it is not possible to remove the protective surface.
Our Instrumentation:
- GE Mentor EM
- Set of probes and scales for surface control
- Set of probes and scales for welding control
The principle of eddy current testing that measures the resistance of a conductive material makes it useful for a wide range of applications, such as conductivity measurement, material sorting, evaluation of heat treatment conditions, material classification based on hardness and strength, thickness thickness measurement of thin components. Compared to other methods of surface flaw detection, a eddy current test requires highly qualified and experienced technicians. The tests are carried out by personnel qualified according to STN EN ISO 9712 Level II and III.
