Magnetic Particle Testing
The magnetic particle method is an inspection technique that detects surface and near-surface flaws in ferromagnetic materials through magnetic leakage fields.
Physical-chemical mechanism of action
Magnetic particle testing uses the property of ferromagnetic materials to induce magnetic fields. When a workpiece is dusted with a powder that moves in magnetic fields (e.g., silicon dioxide), defects like cracks or damage become visible as distortions of the powder.
Metallurgical relevance & welding risks
This method is especially helpful for checking weld quality and integrity. Missing or excessive binding on the surface, cracks, or corrosion can be easily detected. However, if the process is done wrong, it can lead to inaccurate results if the powder is not applied correctly.
Shop practice & action instructions
To apply magnetic particle testing, you need a special device. First, clean the workpiece and dust it with the powder. Then place it in a magnetic field generated by a coil circuit. The distortions in the powder are recorded optically or under a microscope. It's important to control the right amount of powder and the magnetic field strength to get precise results.