• FerroChem NDT Systems Private Limited

Crack Detection with B&W Contrast Spray

In most applications of magnetic particle inspection (MPI), fluorescent magnetic particles are employed because of their superiority in crack detection. Cracks are not to be ?looked for? when fluorescent particles are used ? indications formed attract attention of the viewer not only due to brilliance of illumination but the fluorescence makes the cracks look ten times wider than they actually are. But when the components to be crack detected are big in sizes and/or when the crack detection has to be carried out in the open, the conditions for inspection suitable for fluorescent particles cannot be satisfied, as a result the advantages of inspection by using fluorescent particles is lost. Inspection in open can be made effective by providing a white background on the job surfaces coupled with use of highly sensitive black magnetic particles. FerroChem has now introduced handy self-spray aerosol cans of black ink and white contrast coat for the purpose. The white contrast coat can be applied on cleaned and dried job surface chosen for crack detection by applying a uniform spray. The coating thickness, which is in microns, does not interfere with crack detection. Moreover, the coat dries off in less than 60 seconds. Magnetic particle inspection can then be carried out as per the standard practice. Black particles available in aerosol cans are sprayed on the component surface. Black magnetic particles being very fine and highly sensitive form cracks on the surfaces immediately. The indications formed, which are easily noticeable because of the white background, match the indications formed by fluorescent particles. The use of black ink with white contrast thus makes the inspection effective and easier for components which are big or which are to be tested in open.