Magnetic Particle Examination method may be applied to detect cracks and other discontinuities on or near the surfaces of ferromagnectic materials.
Prior to magnetic particle examination, the surface to be examined and all adjacent areas within at least one inch of the testing area shall be dry and free of all dirt, grease, scale, welding flux and spatter or extraneous matter that may interfere with the examination.
On completion of the above operation, the magnetic field may then be applied to the surface of the part to be examined. The flourescent magnetic ink shall then be applied to the weld area. At least two separate examinations shall be performed on each area. During the second examination the lines of magnetic flux shall be approximately perpendicular to those used during the first examination.
The magnetic field is to be “ON” during all examinations and during the application of the magnetic ink. At no time shall examinations be examined 135 oF in temperature.
Indications will be revealed by retention of magnetic particles. All such indications are not necessarily imperfection, however, since excessive surface roughness, magnetic permeability variations (such as the edge of heat affected zones) etc, may produce similar indications. If indications are believed to be non-relevant, each type of indication shall be explored to determine if relevant linear discontinuities are present.