Magnetic Particle Inspection (MT)

What is Magnetic Particle Testing (MT)?

The magnetic particle method is a non-destructive testing (NDT) method, suitable for detecting surface discontinuities such as cracks, lack of fusion/bonding defects, and laminations, etc. in ferromagnetic materials.
The method makes use of the fact that a surface discontinuity in a magnetized ferromagnetic component will disturb the magnetic field in the component.
By using this effect, the magnetic particles gather along the crack and make an otherwise invisible crack visible.
 

The magnetic particle method has many valuable advantages when inspecting ferromagnetic materials:

- It is one of the safest and most sensitive methods for finding surface cracks.
- The method is fast, simple, and inexpensive.
- Indications are formed directly on the surface of the component.
- The method is not affected by possible deposits in the cracks, such as oil, grease, or other metals.
- The method can be used even on components with small paint thicknesses.
- No major requirements are placed on surface pre-cleaning of the component.
- The examination can be documented by photos and tape lifts, etc., since the indication is an image of the discontinuity.
- Simple and robust equipment results in low investment and maintenance costs.