Eddy current testing is a non-destructive inspection method that leverages the electromagnetism principle to find flaws in conductive materials. Eddy current testing benefits business owners as it aptly detects changes such as near-surface discrepancies and thickness differences that may influence the current and voltage flowing through the coil.
This post delves into the fundamentals of eddy current testing. Continue reading to find out more!
What is Eddy Current Testing?
This non-destructive testing (NDT) evaluation technique is used for a number of tasks, such as measuring material and coating thickness, detecting flaws, identifying materials, and determining the state of heat treatment of particular materials.
As mentioned earlier, eddy current testing plays with the electromagnetism principle. A coil powered by an alternating current is then placed near the test surface, creating a fluctuating magnetic field that produces eddy currents in its proximity.
Using a receiver-coil, any changes to the alternating current flowing in the primary excitation-coil are recorded, together with variations in the changing phases and magnitude of these eddy currents.
Differences in electrical conductivity, the magnetic permeability of the test material and the existence of any discontinuities will lead to an alteration in the eddy current and a subsequent change in the phases and amplitude of the recorded current. Changes are displayed on a screen, and defects are found by interpreting those changes.
How Does Eddy Current Testing Work?
Eddy current testing relies heavily on electromagnetic induction. An alternating magnetic field forms around a conductor, such as a copper coil, when an alternating current is carried through it.
The field changes size as the alternating current rises and falls. According to Lenz’s Law, the fluctuating magnetic field surrounding the coil permeates the material and produces an eddy current to flow in the conductor.
In turn, this eddy current creates a magnetic field of its own. The current and voltage flowing in the coil are impacted by this “secondary” magnetic field, which is in opposition to the “main” magnetic field.
The Applications of Eddy Current Testing
Extremely multi-faceted, eddy current testing benefits people from various sectors for different reasons.
Examination of components or materials, including:
- Welded joints
- Steel tubes
- Bores of bolt holes
- Friction stir welds
- Gas turbine blades
- Cast iron bridges
Flaws detection, such as:
- Surface-breaking flaws
- Linear flaws
- Cracks and corrosion
- Absence of fusion
Other examples of applications:
- Identification of various alloys, including those made of aluminium, as well as both ferrous and non-ferrous metals
- Creating the conditions for the heat treatment
- Identifying conductive and non-conductive coatings
- Metals’ heat treatments are verified
Eddy Current Testing Benefits
Intrigued about eddy current testing benefits? Listed below are some of the many eddy current testing benefits in Malaysia:
- Rapid testing method with reliable test results
- Requires minimal and simple preparation
- Suitable for both ferrous and non-ferrous materials
- Suitable for various sizes and shapes of objects
- Uses light and portable equipment
- Every finding is recorded and available for a long time
- Identify surface cracks and near-surface fissures as small as 0.5 mm
- Identify flaws over multiple layers, including non-conductive surface coatings
Trusted Eddy Current Testing Services in Malaysia
Xpert Engineering delivers professional eddy current testing services to protect your equipment and prevent future complexities. Transform your business by engaging our effective and efficient NDT services.