Magnetic Flux Leakage

The Magnetic Flux Leakage (MFL) inspection technique is a Non-Destructive Testing method that is used to detect thickness loss due to corrosion in ferromagnetic materials in storage tanks and pipes.

The equipment used in this technique uses permanent magnets with high magnetization power which magnetize the section on which they are superimposed, generating a magnetic field in the thickness of the piece. When there is a variation in the thickness of the piece due to a loss of thickness due to corrosion, the field generated in the piece is distorted, causing a “leak” of the field, which is interpreted electronically by the equipment as a loss signal.

The intensity of this signal is interpolated with known values of material loss. The equipment is mainly used in the inspection of the floor plates of storage tanks, complying with the provisions of the API-653 code. It is also used in pipelines. carbon steel, which must be free of any coating and must simply be painted and have direct access to the body of the pipe.