Magnetic Particle Inspection Level 1 Practice Exam

How does magnetic particle testing primarily operate?

1. By using ultrasonic waves

2. By applying a magnetic field and fine particles

3. By measuring electrical conductivity

4. By visual inspection only

The correct answer is: By applying a magnetic field and fine particles

Magnetic particle testing operates on the principle of applying a magnetic field to a ferromagnetic material and introducing fine magnetic particles to the surface. When the magnetic field is applied, it magnetizes the material, and any discontinuities such as cracks or laps within the material will disrupt the magnetic field. These disruptions cause magnetic flux leakage, which can then attract the fine particles that have been applied. The particles, typically in a liquid suspension, adhere to the areas where the magnetic field is disrupted, creating visible indications of the flaws on the surface of the material. This method is particularly useful for detecting surface and slightly subsurface discontinuities and is highly effective in various industrial applications, especially for welds, castings, and forgings. While other methods mentioned can be used for inspecting materials, magnetic particle testing uniquely relies on the interaction of magnetic fields and particles to reveal flaws. This specific approach sets it apart from techniques that utilize ultrasonic waves, measure electrical conductivity, or rely solely on visual inspection.