Eddy Current Testing
Eddy current testing induces electrical current loops in metal to detect cracks and coating thickness. Any disturbance changes the coil impedance and is measured.
Physical-Chemical Mechanism of Action
Eddy current testing uses electromagnetic fields to induce an electrical current disk in the metal. This current generates magnetic flux lines that are disturbed by cracks or layer thicknesses. These disturbances change the coil's impedance, which is detected and measured.
Metallurgical Relevance & Risks in Welding
Eddy current testing is especially useful for highly conductive materials like steel. It can precisely detect cracks, layer thickness differences, and conductivity changes. However, incorrect settings or faulty equipment can produce missing or exaggerated results, leading to wrong conclusions.
Workshop Practice & Instructions
For correct eddy current testing, it's crucial that the metal is clean and free of dirt. Place the coil near the area to be tested to achieve maximum resolution. Set the generator voltage so that impedance changes are clearly visible. If results are missing or unclear, check settings and calibrate the device.