Eddy Current Testing

We provide individual and serial inspection of your components for cracks with eddy current testing.

Non destructive testing with Eddy Current Testing (ET)

What is eddy current testing?

Eddy current testing (ET testing) is a surface crack detection method. Here, electromagnetic induction is used to detect surface defects and near-surface defects. In this method of non-destructive material testing, electromagnetic currents are generated in the component. Because these swirl in a circle, the method is called eddy current testing. Defects in the material change the course of these eddy current lines, allowing defects to be detected.

How does eddy current testing work?

The component is scanned with an eddy current probe. This contains a small sensor with an excitation and receiver coil. The excitation coil of the probe generates an eddy current in the material. The probe is moved along the component according to the expected orientation of the cracks. If the orientation is not known, the component is scanned in different orientations.

If the operator moves the probe over a flaw in the material, the eddy current lines deflect away from the flaw and the electrical conductivity decreases. This change is registered by the receiver coil of the probe and the eddy current tester records a deflection.

When is eddy current testing used?

Eddy current testing is used to detect defects on the surface and near-surface defects in the material.*.

Detectable defects are:
Cracks

Special requirements:
The material to be tested must be electrically conductive

Smallest detectable defect:
From 0.05 mm to 0.15 mm crack depth, very dependent on usable frequency and material

Detectable flaw location:
Flaw detection up to approx. 2 mm for iron, 20 mm for copper and 100 mm for austenite below the surface, at higher frequencies and thus also higher sensitivities for small flaws the penetration depths become up to 100 times smaller, i.e. e.g. only 0.1 mm for steel or 1 mm for austenite.

* The specifications depend on the geometry and physical properties of the material to be inspected and are therefore only intended as a guide.

Eddy Current Testing with VOGT Ultrasonics

We test your components either single or in series in our VOGT test center in Burgwedel (Hanover) or directly at your site.