This is a method that is used to find surface and near surface flaws in ferromagnetic materials like carbon & steel. It is primarily used in surface crack detection. This method works by magnetizing a ferromagnetic specimen using a magnet, a contrast white spray with iron granulated milled black ink filings.

If the specimen has discontinuity, the magnetic field flowing through the specimen is interrupted and the leakage field occurs. A white contrast reagent is sprayed on the surface of the specimen. Thereafter, granulated milled iron particles coated with a dye pigment are applied to the specimen. These filings are attracted to leakage fields and cluster to form an indication directly over the discontinuity.

The basic procedure that is followed to perform magnetic particle testing consist of the following.

• Pre-cleaning of the specimen
• Introduction of the white contrast reagent and magnetic
• field
• Application of black iron filings on media
• Interpretation of magnetic particle indications