Which nondestructive testing method uses magnetization and iron powder to reveal surface flaws on steel components?

• A. Magnetic Particle Testing
• B. Radiographic Testing
• C. Ultrasonic Testing
• D. Acoustical Testing

Answer: (A)

Magnetic Particle Testing relies on magnetizing a ferromagnetic steel component and applying iron powder so that surface and near‑surface flaws show up as visible indications. When the part is magnetized, the magnetic flux travels along the material and defects disrupt the field, causing leakage that attracts the iron particles into a pattern that highlights the flaw’s location and orientation. This method is particularly effective for surface-breaking cracks on steel because the indications appear where the magnetic field is disturbed, and it’s fast, portable, and non-destructive. Surface preparation helps the particles reveal fine details, and after inspection the part is cleaned to remove the residual powder.

This fits the description of using magnetization and iron powder to reveal surface flaws on steel components. Radiographic testing, by contrast, looks for internal flaws using X-rays; ultrasonic testing uses sound waves to detect subsurface features; acoustical testing relies on sound characteristics and does not use magnetization or iron powder.