Which examination method uses a magnetic field and a finely divided powder to reveal defects?

Which examination method uses a magnetic field and a finely divided powder to reveal defects?

• A. Ultrasonic
• B. Liquid Penetrant
• C. Magnetic Particle
• D. Radiographic

Answer: (C)

Magnetic Particle testing uses a magnetic field to reveal defects. When the part is magnetized, any discontinuity such as a crack disrupts the magnetic flux, creating leakage fields. Finely divided ferromagnetic powder (dry or fluorescing with a UV light) is applied and clusters at the leakage field, forming a visible indication that traces the flaw on or just beneath the surface. This makes it especially effective for surface and near-surface defects in ferromagnetic materials. Proper surface cleaning and demagnetization after testing are important steps. In contrast, ultrasonic testing uses sound waves, liquid penetrant relies on dye seeping into surface openings, and radiography uses X-rays to view internal features.

Magnetic Particle testing uses a magnetic field to reveal defects. When the part is magnetized, any discontinuity such as a crack disrupts the magnetic flux, creating leakage fields. Finely divided ferromagnetic powder (dry or fluorescing with a UV light) is applied and clusters at the leakage field, forming a visible indication that traces the flaw on or just beneath the surface. This makes it especially effective for surface and near-surface defects in ferromagnetic materials. Proper surface cleaning and demagnetization after testing are important steps. In contrast, ultrasonic testing uses sound waves, liquid penetrant relies on dye seeping into surface openings, and radiography uses X-rays to view internal features.