Which nondestructive testing method is suitable for the inspection of most metals, plastics, and ceramics for surface and subsurface defects?

Which nondestructive testing method is suitable for the inspection of most metals, plastics, and ceramics for surface and subsurface defects?

• A. Eddy current inspection
• B. Magnetic particle inspection
• C. Ultrasonic inspection
• D. Radiographic inspection

Answer: (C)

Ultrasonic testing works by sending high-frequency sound waves into a material and listening for echoes that return from flaws or boundaries. This approach can probe metals, plastics, and ceramics because sound waves travel through these materials and reflect off discontinuities such as cracks, voids, or inclusions, giving information about both the presence and the depth of defects. With proper coupling and appropriate probe frequency, you can inspect various thicknesses and complex shapes and still size defects accurately. Eddy current testing is great for surface and near-surface flaws in conductive metals but doesn’t work well for nonconductive plastics and ceramics, and it’s limited in depth. Magnetic particle inspection detects surface or near-surface flaws in ferromagnetic materials and requires magnetic properties. Radiographic inspection can image internal features but involves radiation, safety considerations, and may be less effective for certain geometries or very small flaws. Ultrasonic testing thus offers broad applicability across metals, plastics, and ceramics for both surface and subsurface defect detection.

Ultrasonic testing works by sending high-frequency sound waves into a material and listening for echoes that return from flaws or boundaries. This approach can probe metals, plastics, and ceramics because sound waves travel through these materials and reflect off discontinuities such as cracks, voids, or inclusions, giving information about both the presence and the depth of defects. With proper coupling and appropriate probe frequency, you can inspect various thicknesses and complex shapes and still size defects accurately.

Eddy current testing is great for surface and near-surface flaws in conductive metals but doesn’t work well for nonconductive plastics and ceramics, and it’s limited in depth. Magnetic particle inspection detects surface or near-surface flaws in ferromagnetic materials and requires magnetic properties. Radiographic inspection can image internal features but involves radiation, safety considerations, and may be less effective for certain geometries or very small flaws. Ultrasonic testing thus offers broad applicability across metals, plastics, and ceramics for both surface and subsurface defect detection.