Magnetic particle inspection (MT) is a type of non-destructive test (NDT) that allows surface and subsurface discontinuities to be detected in ferromagnetic materials. The physical principle of this method consists of the distortion of the magnetic field in the areas where the material has discontinuities perpendicular to the field lines. It is a very extensively used test mainly due to the speed of the inspection, the flexibility for detecting small discontinuities at a low cost with high portability. However, there are a series of disadvantages that have led to the search for alternatives to this inspection method, such as: the limitation of materials that can be inspected (only ferromagnetic materials), the limitation of the type of detectable discontinuities (only linear discontinuities perpendicular to the magnetic field lines), the management of the magnetic particles at the end of their life cycle (waste management), the need to de-magnetise the materials after inspection, the difficulty in automating the inspection, among others.
In this work, a comparative study of different types of non-destructive tests based on electromagnetic technology, active infrared thermography and ultrasounds has been carried out. The results obtained confirm the capacity of the various studied techniques to replace the magnetic particle inspections.