Magnetic Particle  Inspection is used to detect surface breaking defects in  metallic welds and  material.  Whether it is testing welds on structural steel in accordance with BS EN 1090 for CE marking or testing materials post machining.  Worcester NDT can provide Magnetic Particle  Inspection at your site anywhere in the UK. For larger production runs of forgings, castings or  machined parts,  an in-house bench machine is used.

On-Site:  Magnetic Particle Inspection.
AC 110v or 240v Yoke
Testing Welds, Materials and Machined Parts
This method of NDT may detect surface breaking discontinuities in welds and material. MPI can only be used on ferromagnetic materials. First a contrasting white paint is sprayed onto the component, then a magnetic field is introduced into the area to be tested, using a portable yoke.

Fine ferromagnetic particles in a liquid suspension are then applied to the test area. 
Any discontinuity which interrupts the magnetic lines of force will create a leakage field which has a north and south pole either side of it. This attracts the ferromagnetic particles in great numbers. The discontinuity may show as a black or fluorescent indication against the contrasting background.

In-House:  Magnetic Particle Inspection.
Bench machine.
Testing Castings, Forgings and Machined Parts.
A bench machine is used to detect surface breaking discontinuities in batch runs of the same component. The magnetic current is introduced via a movable  head and tail stocks that  clamp the component.

A fluorescent ink, which is more sensitive, is used and the results are viewed under an ultraviolet light. Also, by using DC or half wave rectified current, sub-surface discontinuities of up to 2mm below the surface may be found.