Which nondestructive testing method uses a magnetic field and iron particles to reveal defects?

Which nondestructive testing method uses a magnetic field and iron particles to reveal defects?

• A. Magnetic particle testing
• B. Liquid penetrant testing
• C. Ultrasonic testing
• D. Radiographic testing

Answer: (A)

Magnetic particle testing uses a magnetic field and iron particles to reveal defects. When a ferromagnetic material is magnetized, any surface or near-surface flaw causes flux leakage at that defect. The iron particles then gather at these leakage areas, forming a visible indication that shows where the flaw lies. This method is especially sensitive to small surface-connected or slightly subsurface defects and works best on ferromagnetic materials. It’s common to apply the magnetizing field with clamps, yokes, or coils, and then inspect with either dry iron particles or suspended/fluorescent particles for easier visibility. Liquid penetrant testing, ultrasonic testing, and radiographic testing are different approaches: dye penetrant highlights surface-breaking flaws by seeping into openings; ultrasonic uses high-frequency sound waves to detect internal flaws by reflections; and radiographic uses X-ray or gamma rays to image internal structures.

Magnetic particle testing uses a magnetic field and iron particles to reveal defects. When a ferromagnetic material is magnetized, any surface or near-surface flaw causes flux leakage at that defect. The iron particles then gather at these leakage areas, forming a visible indication that shows where the flaw lies. This method is especially sensitive to small surface-connected or slightly subsurface defects and works best on ferromagnetic materials. It’s common to apply the magnetizing field with clamps, yokes, or coils, and then inspect with either dry iron particles or suspended/fluorescent particles for easier visibility.

Liquid penetrant testing, ultrasonic testing, and radiographic testing are different approaches: dye penetrant highlights surface-breaking flaws by seeping into openings; ultrasonic uses high-frequency sound waves to detect internal flaws by reflections; and radiographic uses X-ray or gamma rays to image internal structures.