Scientific principles behind magnetic testing

A magnetic field is applied to a component made from ferromagnetic material. The magnetic lines of force travel through the material, and exit and re-enter the material at the poles. Defects such as crack or voids cannot support as much flux, and force some of the flux outside of the part. Magnetic particles distributed over the component will be attracted by the areas of flow leakage and will give a visible indication.

Main uses

Used to inspect ferromagnetic materials (those that can be magnetized) for defects that result in a transition in the magnetic permeability of a material. Magnetic particle inspection can detect surface and near-surface defects.

Main advantages of magnetic testing

• large surface areas of complex parts can be inspected rapidly;
• can detect surface and sub-surface flaws;
• surface preparation is less critical than it is in penetrating inspection;
• magnetic particle indications are produced directly on the surface of the part and form an image of the discontinuity;
• equipment costs are relatively low.

Inspections & Surveys

At Ned Marine we provide comprehensive inspections and surveys for many of our clients. Do you want to assess the condition, safety, and compliance of your vessels, offshore structures, or industrial assets? Our certified surveyors conduct pre-conditional surveys, special surveys, and hull inspections, identifying structural issues, corrosion, or coating failures before they become costly problems.

We work globally, on land, in dock, and at sea, ensuring compliance with classification societies and industry regulations. Whether for preventive maintenance or regulatory requirements, our inspections deliver clear, detailed reports to help you make informed decisions and maintain operational excellence.

Our Non-Destructive Testing (NDT) services:

Ultrasonic Testing | Magnetic Testing | Penetrant Testing | Visual Inspection | Vacuum Box Testing | Eddy Current Testing