Eddy Current

When a magnetic field cuts through metal, a current is induced. If a magnetic field cuts a wire in a closed circuit, a current is induced round the circuit. However if a magnetic field cuts through a sample of metal that is not connected to a circuit, an Eddy Current is produced. This eddy current is localized in the metal and has a flow pattern. The flow pattern is disturbed by discontinuities from the surface to a shallow depth of penetration. The method is quick and very sensitive. No contact with the metal is required. All metals may be subject to this form of testing.

• Acquaintance with the relevant equipment
• Practice with coils
• Practice with weld samples
• Location and assessment of discontinuities
• Report

• Review of electromagnetic theory
• Factors that affect coil impedance and flux leakage fields
• Signal to noise ratio
• Selection of test frequency
• Selection of method of magnetization for flux
• Leakage testing
• Coupling
• Field strength and its selection
• Field orientation for flux leakage testing
• Relevant standards
• Reporting method
• Material technology
• Assessment of discontinuities

With the completion of the training the candidate can sit the examinations for certification according to SNT-TC-1A. Training and Examinations shall be done in English only.