Magnetic particle examination is primarily used for detecting which of the following types of discontinuities?

Magnetic particle examination is primarily utilized to detect surface and near-surface discontinuities in ferromagnetic materials. This non-destructive testing method involves magnetizing the part being inspected, which causes magnetic particles to accumulate at areas where there are flaws, such as cracks or other surface irregularities.

The primary advantage of this method lies in its ability to reveal defects that are not easily seen by the naked eye, particularly those that are close to the surface. Surface discontinuities are critical to identify because they can significantly affect the integrity and performance of a component.

While other types of discontinuities, such as internal defects and those specifically related to welds or heat-affected zones, are critical in structural integrity, they are not best suited for detection with magnetic particle examination. For internal discontinuities, techniques such as ultrasonic testing or radiographic testing would be more appropriate.