Which examination technique is NOT used in magnetic particle examination?

The magnetic particle examination (MPE) technique is primarily designed for detecting surface and near-surface flaws in ferromagnetic materials by using magnetic fields and fine magnetic particles. The correct choice indicates the option that is not part of this examination method.

In magnetic particle examination, methods such as the yoke, prod, and circular techniques are employed to create a magnetic field that helps in detecting flaws. The yoke method uses a magnetic yoke to produce magnetic flux, while the prod method utilizes a direct electrical current passing through a material to generate a magnetic field. Circular methods often involve the application of magnetic fields in a circular pattern around the test piece to effectively highlight surface defects.

Ultrasonic testing, however, is an entirely different non-destructive testing method that relies on high-frequency sound waves to detect internal flaws within materials. It operates on different principles than those employed in magnetic particle examination and is not suitable for magnetic particle techniques, which focus on magnetic properties rather than sound wave propagation. Thus, ultrasonic testing does not belong in the context of magnetic particle examination methods.