Magnetic Particle Inspection Level 1 Practice Exam

Which process is used to detect surface discontinuities in metals?

1. Radiographic testing

2. Magnetic particle testing

3. Ultrasonic testing

4. Visual inspection

The correct answer is: Magnetic particle testing

Magnetic particle testing is specifically designed to detect surface and near-surface discontinuities in ferromagnetic materials. This non-destructive testing method involves magnetizing the material and applying fine magnetic particles, which may be dry or suspended in a liquid. When there are surface defects such as cracks, voids, or inclusions, the magnetic field is interrupted, causing the particles to gather at the discontinuities and form indications. This technique is highly effective for identifying flaws that could impact the integrity and performance of metal components. Other processes mentioned, such as radiographic testing, ultrasonic testing, and visual inspection, serve different purposes. Radiographic testing utilizes X-rays or gamma rays to reveal internal flaws, while ultrasonic testing employs high-frequency sound waves to detect subsurface imperfections. Visual inspection involves a direct examination of the surface but is limited by the inspector's ability to perceive discontinuities and cannot confirm their nature or significance. Thus, magnetic particle testing remains the most suitable answer for detecting surface discontinuities.