Magnetic particle inspection is a nondestructive testing method used for surface and near surface defect detection. MPI is a fast and relatively easy to apply and 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, such as iron filings to detect flaws in components. The only requirement is that the component being inspected must be made of a ferromagnetic material such 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 such as 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 include