Magnetic Particle Inspection

Magnetic particle testing, sometimes called mag particle, MPI, or MT, is ideal for identifying surface or near-surface discontinuities in parts and assemblies whose materials have a certain degree of magnetism, such as billets, bars, castings, forgings, fasteners, weldments, brazes, and extrusions.

How does magnetic particle examination work?

Magnetic particle inspection is a nondestructive 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 and the piece is magnetized by direct or indirect magnetization.

Wet MT and dry MT methods

The presence of a surface or subsurface defect or discontinuity in the material allows the magnetic flux to leak. Ferrous iron particles are applied to the part in a dry or in a wet suspension, these variations can be referred to as dry magnetic particle inspection or wet magnetic particle inspection. If an area of flux leakage is present, the particles will be attracted to the defect. The particles will build up around the leakage and form an "indication." The indication is evaluated to determine its characteristics, its cause, and how to proceed.

Element's ASNT-certified nondestructive testing experts

Element MT inspectors are certified to American Society of Nondestructive Testing (ASNT) Level III and Level II. By examining the nature, location, and extent of an indication, our highly trained and experienced inspectors can determine the origin and cause of both surface and near-surface discontinuities. Element operates full-service NDT and magnetic particle testing labs that utilize a variety of advanced equipment capable of performing quality inspections for virtually any form of ferrous material, component, or assembly.

Field and in-lab magnetic particle testing services

Mag particle inspection can be performed by Element NDT technicians in the laboratory or in the field. A partial list of our MT equipment includes:

  • Magnaflux MD3-1060L 5600 Amps:

    A multi-directional stationary mag machine that features a 100-inch bed. This state-of-the-art equipment facilitates high-quality inspections in half the time of a conventional mag unit and reduces handling requirements, thereby decreasing lead times and increasing productivity.

  • Magnaflux 5600 Amps with 1,000 Pound Hoist 

    Also featuring an 100-inch bed and multi-directional testing capabilities, this unit accommodates exceptionally heavy test specimens. In addition, both mag machines are forklift accessible, facilitating testing of parts up to 12,000 pounds.

  • Hand-held Yokes, Prods, and Cables
    These portable devices accommodate onsite inspections of larger components.

Mag Particle Testing in your industry


Element supports today’s precision aerospace, military, nuclear, and commercial industries with Magnetic Particle Inspections and other nondestructive testing (NDT) services.