Which of the following describes the procedure for magnetic particle inspection?

• A. Clean the part, magnetize it as directed by the service manual, flow the indicating medium over the surface, and inspect under a 'black' light. When the inspection is complete, thoroughly demagnetize the part.
• B. Clean the part, magnetize it as directed by the service manual, inspect under a 'black' light, flow the indicating medium over the surface, and demagnetize the part.
• C. Clean the part, flow the indicating medium over the surface, magnetize it, inspect under a 'black' light, and demagnetize the part.
• D. Magnetize the part first, then clean it, apply the medium, and inspect.

Answer: (A)

In magnetic particle inspection, you first prepare the surface, then create a magnetic field in the part, apply the indicating medium, inspect for indications under the proper lighting, and finally remove the magnetism. Cleaning ensures oils, dirt, and contaminants don’t mask or imitate flaws and helps the magnetization travel evenly through the area of interest. After cleaning, you magnetize the part according to the service manual, choosing the correct method and polarity so the flux paths reveal any defects where they’re likely to occur. With the part magnetized, you flow or apply the indicating medium over the surface so the small particles are drawn toward leakage fields at cracks or seams. You then inspect under the appropriate lighting, typically using a black light for fluorescent indicators to expose faint indications. After the inspection, you demagnetize the part to remove residual magnetization, which helps prevent erroneous indications and makes handling safer. This sequence is why the described procedure is correct.