to Magnetic Particle Inspection
Magnetic particle inspection (MPI) is a nondestructive testing method
used for defect detection. MPI is fast and relatively easy to
apply, and part surface preparation is not as critical as it is
for some other NDT methods. These characteristics make MPI one
of the most widely utilized nondestructive testing methods.
MPI uses magnetic fields and small magnetic particles (i.e.iron filings) to detect flaws in components. The only requirement
from an inspectability standpoint is that the component being
inspected must be made of a ferromagnetic material such as iron,
nickel, cobalt, or some of their alloys. Ferromagnetic materials
are materials that can be magnetized to a level that will allow
the inspection to be effective.
The method is used to inspect a variety of product forms including castings, forgings, and weldments. Many different industries
use magnetic particle inspection for determining a component's
fitness-for-use. Some examples of industries that use magnetic
particle inspection are the structural steel, automotive, petrochemical,
power generation, and aerospace industries. Underwater inspection
is another area where magnetic particle inspection may be used
to test items such as offshore structures and underwater pipelines.