MAGNETIC PARTICLE INSPECTION

Magnetic particle Inspection ( MPI ) is a non destructive testing (NDT) process for detecting surface and slightly subsurface discontinuities in ferromagnetic materials such asiron, 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 magnetic lines of force are perpendicular to the direction of the electric current which may be either alternating current (AC) or some form of direct current (DC) (rectified AC)

italicPemeriksaan partikel magnetik (MPI) adalah proses pengujian non destruktif (NDT) untuk mendeteksi diskontinuitas permukaan dan sedikit di bawah permukaan bahan feromagnetik seperti baja, nikel, kobalt, dan beberapa paduannya. Prosesnya menempatkan medan magnet ke bagian tersebut. Potongan dapat dimagnetisasi dengan magnetisasi langsung atau tidak langsung. Magnetisasi langsung terjadi ketika arus listrik dilewatkan melalui benda uji dan medan magnet terbentuk pada material. Magnetisasi tidak langsung terjadi bila tidak ada arus listrik yang melewati benda uji, namun medan magnet diaplikasikan dari sumber luar. Garis-garis magnetik gaya tegak lurus terhadap arah arus listrik yang mungkin merupakan arus bolak-balik (AC) atau beberapa bentuk arus searah (DC) (AC yang diperbaiki)

The presence of a surface or subsurface discontinuity in the material allows the magnetic flux to leak, since air cannot support as much magnetic field per unit volume as metals. Ferrous iron particle are then applied to the part. The particles may be dry or in a wet suspension. 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 taken, if any.

A popular name for magnetic particle Inspection is or used to be magnafluxing, The company of the same name was one of the early manufacturers of equipment and materials for the process.