When using DC magnetization with Magnetic Particle Inspection (MPI), you are able to detect which types of defects?

Using DC magnetization in Magnetic Particle Inspection (MPI) is particularly effective for detecting both surface defects and linear near-surface defects. This method generates a magnetic field in the material under inspection, enabling the detection of discontinuities that interrupt the magnetic flux.

Surface defects, such as cracks and laps, can easily be detected because they are aligned with the applied magnetic field, allowing the magnetic particles to cluster at the surface and indicate the presence of these flaws. Linear near-surface defects, which may not penetrate deeply, are also detectable using this method, as the magnetic field can still be influenced by these types of discrepancies just beneath the surface.

The inclusion of surface and linear near-surface defects in the correct answer reflects the utility of DC magnetization in highlighting flaws that might be missed by methods that only focus on deeper or volumetric discontinuities. Detection of only sub-surface defects would not provide a complete assessment of the material's integrity, and while one might think that all types of defects could be detected, MPI is primarily sensitive to those adhering to the magnetic field created, which predominantly affects surface and near-surface issues. Thus, the correct answer emphasizes the specific advantages provided by DC magnetization in MPI.