Magnetic Particle Inspection
(MPI) is a non-destructive testing (NDT) process for detecting surface and subsurface discontinuities in ferroelectric materials such as iron, nickel, cobalt, and some of their alloys. The process puts a magnetic field into the part. The piece can be magnetized by direct or indirect magnetization. Direct magnetization occurs when the electric current is passed through the test object and a magnetic field is formed in the material. Indirect magnetization occurs when no electric current is passed through the test object, but a magnetic field is applied from an outside source.
The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak. Ferrous iron particles are applied to the part. If an area of flux leakage is present the particles will be attracted to this area. The particles will build up at the area of leakage and form what is known as an indication. The indication can then be evaluated to determine what it is, what may have caused it, and what action should be taken, if any.
What are the advantages of magnetic particle inspection?
- Test method process is quick and simple in principle and application.
- Highly sensitive to the detection of surface and slightly subsurface linear indications.
- Test method process may often work through contaminant layers and coating thickness.
- Indications appear on the actual test part.
- The method lends itself to automation and high volume production inspection.
- Less expensive than other more sophisticated methods of quality assurance.
Just some of the MPI inspections that can help you safely, avoid incidents and OSHA fines!
- Crane Hooks
- Lifting Beams
- Lift Truck Forks
- Special Lift Devices