Eddy current probe inspection with rotating ferrite cores
Eddy current probe testing with rotating ferrite cores is a method for rapid and gapless detection of longitudinal and transverse flaws in bores or tubes. By rotating the magnetic field, cracks are detected regardless of orientation.
Physico-Chemical Mechanism of Action
The rotating probe uses a rotating magnetic field generated by a ferrite core. This core rotates rapidly, creating a dynamic magnetic field that circulates in the test zone. The magnetic lines continuously change direction, allowing cracks to be detected regardless of their orientation.
Metallurgical Relevance & Welding Risks
This test method is especially useful for detecting micro-defects and cracks in weld areas. A faulty test can lead to inaccurate results if the magnetic field is not correctly aligned or not rotating fast enough. This can result in missed defects that may cause issues later in service.
Workshop Practice & Instructions
To perform a successful rotating probe test, follow these steps:
1. Set up the device: Make sure the magnetic field rotates fast enough (typically at least 500 rpm) and the test zone is correctly aligned.
2. Prepare the bore or pipe: Remove all metal particles and dirt from the test zone to ensure clear signal detection.
3. Insert the probes: Place the probes in the bore or pipe and run the test.
4. Interpret the results: Analyze the signals for anomalies that could indicate cracks or other defects. Use specialized software for evaluation to get accurate results.