Magnetic Particle Inspection Level 2 Practice Exam

What type of defects are indicated by broken lines parallel with the axis on some inspected pieces?

1. Shrinkage

2. Machining tears

3. Surface checking

4. Nonmetallic inclusions

The correct answer is: Nonmetallic inclusions

The presence of broken lines that run parallel to the axis on inspected components is typically indicative of nonmetallic inclusions. These inclusions—such as oxides, sulfides, or other foreign materials—can interrupt the uniformity of the metal and can create linear discontinuities in the magnetic field during inspection. As the magnetic particles are drawn to these defects, they will align along the broken lines, clearly showcasing their presence. This is important in the context of quality control and material integrity, as nonmetallic inclusions can affect the mechanical properties of the metal, potentially leading to failure in service. Inspecting for these types of defects is crucial in industries such as aerospace and automotive, where structural integrity is paramount. Other defect types, while they may exhibit visual indicators, do not typically manifest as broken lines parallel with the axis. For example, shrinkage typically produces irregular voids, machining tears may show more chaotic or uneven patterns, and surface checking is usually characterized by crack-like discontinuities rather than consistent linear indications. Understanding these different types of defects and their visual cues helps inspectors accurately identify the state of the materials they are evaluating.