Which nondestructive testing method involves magnetization of the area under test and uses iron powder to reveal surface flaws, commonly on steel aerial devices?

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

Answer: (C)

Magnetic Particle Testing detects surface and near-surface flaws in ferromagnetic materials by magnetizing the area under test and applying iron powder. When the material is magnetized, any crack or flaw disrupts the magnetic field and causes flux leakage at the defect. The iron powder is drawn to these leakage paths, collecting along the flaw and creating a visible indication on the surface that engineers can interpret. This method is especially well-suited for steel aerial devices because they are ferromagnetic and often have complex shapes where surface-breaking cracks can hide in joints and bends. It’s fast, relatively inexpensive, and capable of revealing small surface flaws that might not be visible otherwise. It won’t work on nonferrous materials, and it requires proper surface preparation and skilled interpretation.