R-CON NDT is a distributor of Met-L-Chek. Their product line of magnetic particle materials are certified to meet ASTM, ASM, ASME, and Military specifications. Wet method materials are available as powder, aerosol, liquid concentrate, and premixed bath forms. Following is an overview of Met-L-Chek products.

Met-L-Chek Magnetic Particle Inspection Materials

GENERAL INFORMATION

Magnetic particle inspection is used to locate discontinuities on or near the surface of ferromagnetic materials. A magnetic field is induced in the part to be examined. Discontinuities at or near the surface will cause the magnetic field to concentrate. Fine magnetic particles are attracted to the magnetic field leakage over the discontinuities forming indications or mapping the discontinuities. Considerable theory, technical training, specialized equipment and trial and error is involved for effective magnetic particle inspection.

PARTICLES

There are two types of materials generally used for magnetic particle inspection, wet method and dry method. Dry method materials are primarily used in weld inspection. Production and overhaul situations require high sensitivity, and broad detection capability is best achieved by the wet method. Wet method particles are generally smaller than dry method particles and are more easily attracted to weaker leakage fields. The particles are suspended in a liquid carrier fluid which facilitates the mobility of the particles on the part surface. The particles can be of visible or fluorescent illumination.

CONTINUOUS METHOD

Wet method materials may be used with AC, HWDC, or FWDC magnetizing currents. In all three the application of the bath begins and ends before the current shot is ended to insure maximum field strength during bath application. Bath application after the current shot may reduce sensitivity by washing off weakly held particles. Most dry method particle inspections use AC magnetization.

BATH

Special petroleum based carrier fluids or waterr which has been treated with conditioning agents may be used as the wet method particle bath media. The bath must be continuously agitaged during use as the dense particles will settle out of solution upon standing. Materials intended for water bath use should not be placed in equipment that has been used for oil bath applications until the tank and all plumbing have been thoroughly cleaned.

SPECIFICATIONS

The Met-L-Glo series of wet method magnetic particle materials are formulated to meet or exceed the requirements of the most widely used magnetic particle inspection specifications.

ASTM E-709 | ASTM E-1444 | AMS-2641 | AMS-3042 | AMS-3045 | AMS-3046 | AMS-3044 ASME B & PV Code, Sec. V, Article 25.