Check method with magnetic particle (MT) is a type of non-destructive testing suitable to all ferromagnetic materials.
The magnetic particle is based on the analysis of magnetic field variations that occur in the presence of surface or sub surface defects.
During magnetoscopic testing (MT) the component under check is magnetized by a magnetic field and magnetic particles are applied on its surface; consequently, the presence of cracks or defects within the field causes a deviation of the flow lines and, accordingly, of the magnetic particles, which are grouped creating a discontinuity.
Any directions or any defects can be identified by means of natural light (in case of technique with magnetic black particles on white background) or artificial (in case of fluorescent particles).
Normative references of the magnetic particle method are:
- UNI EN 10228-1: Magnetic particle examination of steel forgings
- UNI EN 17638: Controlling magnetic particle examination of welds
- UNI EN 23378: Controlling magnetic particle examination of welds - Acceptance levels
- UNI EN ISO 3059: Magnetic Particle - Terms of vision
- UNI EN ISO 9934-1: Magnetic Particle - General principles
- UNI EN ISO 9934-2: Magnetic Particle - Means of detection
- UNI EN ISO 9934-3: Magnetic Particle - Equipment