Eddy Current Testing (ET)

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. 

This course is orientated towards candidate NDT inspectors. 

Contents

Theory

• Review of electromagnetic theory
• Factors that affect coil impedance and flux leakage fields
• Signal to noise ratio
• Selection of test frequency
• Field strength and its selection
• Selection of method of magnetization for flux
• Coupling
• Relevant standards
• Reporting method
• Material technology
• Assessment of discontinuities
• Practice with coils
• Practice with weld samples
• Location and assessment of discontinuities
• Report

Examinations

Upon completion of the training the participants can attend the exam for certification according to ISO 9712 and SNT-TC-1A.

Examinations are held in two stages, including written and practical. After the written exam is performed to calibrate the device with different probes and discontinues are determined on samples and the preparation of the acceptance report.

Providing sufficient success in the exam then awarded certificates.