Magnetic particle examination (MT) can be a useful nondestructive exam method during new constructution or in-service inspections. For quick, low-cost inspections, MT is often the best NDE method for detecting surface and slightly subsurface discontinuties.
The following visual illustrates steps of dry powder, nonfluroescent, yoke technique of Magnetic Particle testing.
A. The surface to be examined is cleaned using ultrasonic cleaning methods
B. A magnetic field is introduced into the part
C. Ferromagnetic medium is applied while the part is still magnetized
D. Excess ferromagnetic medium is removed with a light air stream from a bulb, syringe, or other source of low pressure dry air
E. Indications are interpreted and evaluated to the applicable accpetance standards
F. The yoke is turned 90 degrees from the original position and steps B - F are repeated.
[Courtesy of Inspection Trends Magazine, Nov. 2016, PP 23-24]