Non-Destructive Testing (NDT) Practice Test

In magnetic particle inspection, what characteristic must the test material possess to be easily magnetized?

1. Low density

2. High conductivity

3. High permeability

4. Low resistivity

The correct answer is: High permeability

In magnetic particle inspection, the ability of the test material to be easily magnetized is primarily determined by its magnetic permeability. High permeability means that the material can easily become magnetized and will respond well to external magnetic fields. This characteristic allows the material to effectively hold the magnetic field, which is essential for the detection of surface and near-surface defects during the inspection process. When a material has high permeability, it means that it offers very little opposition to the establishment of a magnetic field, which enhances the effectiveness of the magnetic particle inspection method. As a result, the magnetic particles can congregate at defects more readily, making them easier to visualize and identify. While factors like density, conductivity, and resistivity affect a material’s overall behavior, they do not directly influence the material's ability to be magnetized in the context of magnetic particle inspection as significantly as permeability does.