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Technique · ET
Eddy Current Testing
A fast electromagnetic method to find surface and near-surface cracks, even through a light coat of paint.
What it is
Eddy Current Testing is a non-destructive testing method that uses electromagnetism to detect surface and near-surface defects.
A coil carrying alternating current induces electrical currents in the material. When a crack is present, the path of these currents changes, and the instrument picks up that change. This makes it possible to inspect ferromagnetic materials and welds through a light coat of paint, without removing the coating.
How the test works
- PreparationThe surface and coating thickness are checked and the right probe is selected.
- CalibrationThe instrument is set up on reference standards with known notches.
- ScanningThe probe is moved over the area of interest, such as the weld cap and toe.
- EvaluationSignal changes are analysed to identify and locate indications.
- ReportResults and recommendations are recorded.
Where we apply it
- Welded joints on painted structures
- Naval and offshore structures
- Lifting equipment such as cranes
- Conductive metal components
What it detects
- Surface cracks
- Near-surface cracks
- Fatigue cracks at the weld toe
Advantages
- No need to remove light coatings, saving time and cost
- Immediate results
- Fast test with no chemicals
- Ideal for periodic inspections
Limitations and precautions
- Only applicable to conductive materials
- Inspection depth limited to the surface and just below it
- Requires reference standards and a qualified technician
Frequently asked questions
Do I need to remove the paint for Eddy Current Testing?
Not for light coatings. This is one of the main advantages of the method. The coating thickness is checked before the test.
Does Eddy Current replace magnetic particle testing?
They are complementary. Eddy Current is advantageous when the paint cannot or should not be removed; magnetic particle testing is widely used on prepared surfaces.
Shall we inspect your equipment?
On site, in the workshop or at your supplier, with a technical report at the end.