What type of materials can be inspected using Magnetic Particle Inspection?

Magnetic Particle Inspection (MPI) is a non-destructive testing method specifically suited for examining ferromagnetic materials. These materials have properties that allow them to be magnetized, making them responsive to magnetic fields. The inspection process involves inducing a magnetic field into the material and then applying ferrous particles, which will cluster around any magnetic flux leakage points, such as discontinuities or cracks.

When ferromagnetic materials are accessible, they can be inspected effectively, as the magnetic field can penetrate the material adequately to reveal surface and, to some extent, subsurface defects. This method is widely used in industries such as aerospace, automotive, and manufacturing, where integrity of the components is critical.

Non-ferromagnetic materials, such as aluminum or titanium, do not have the necessary magnetic properties to display defects using the MPI method. Thus, options that include non-ferromagnetic materials or those that suggest the method applies to all materials do not align with the fundamental principles of Magnetic Particle Inspection. Similarly, the condition of the material, such as having been heat-treated, does not universally rule it out from inspection, provided it retains its ferromagnetic properties, so that stipulation about treatment condition is also incorrect. The method focuses on materials that can be effectively