Magnetic Particle Inspection (MPI) is a non-destructive testing method used for examining a ferrous metal's surface and near surface defects. It makes use of an externally applied magnetic field or half wave DC (rectified AC) current through the material, and the principle that the magnetic susceptability of a defect is markedly poorer than that of the surrounding material. In a dark room using black light the defect will appear much brighter than the surrounding material and it is detected.
MPI: At ATRONA we have two magnaflux machines capable of testing up to 15 foot long samples. Our technicians are trained to perform wet magnetic particle inspection and have years of experience with this test method. We are accredited for this testing by ISO/IEC 17025 and follow the guidlines of ASTM E 1444.
WHEN TO USE MPI: MPI is typically utilized to inspect for surface flaws and cracks after heat treating, induction hardening, welding, straightening, or after the manufacturing process to assure the component has no surface issues. Besides having an accredited test method and qualified operators ATRONA also utilizes its metallurgical staff when there are issues or questions about surface indications and if needed we can perform additional testing to assess the severity or root cause of detected indications.