During an inspection, what might indicate surface defects in most metals?

Surface defects in most metals can be effectively identified through a process known as eddy current inspection. This method involves inducing an electrical current in the metal through the use of a coil. When the current flows, it creates magnetic fields that interact with the conductive material. If there are surface defects such as cracks, corrosion, or other irregularities, these will affect the flow of the eddy currents, revealing their presence.

Eddy current inspection is particularly useful because it is sensitive to small discontinuities and can be applied to various conductive materials. The technique allows for the detection of surface and near-surface flaws without requiring direct contact, making it a non-destructive testing method. This ability to locate surface defects makes eddy current inspection a preferred choice for inspections where surface integrity is critical, such as in aerospace components, automotive parts, and other critical structures.

Visual inspection, while a fundamental method for identifying surface issues, heavily relies on the inspector's ability to see and interpret visual cues and may miss defects that are not easily observable. Radiographic testing and ultrasonic testing, although effective for other types of defects (like volumetric flaws), are not specifically designed to prioritize surface defects as efficiently as eddy current inspection.