Which method is primarily used for visual inspection in non-destructive testing?

The method primarily used for visual inspection in non-destructive testing is visual inspection itself. This technique involves the direct observation of an object or component to identify any visible defects or irregularities. Visual inspection relies on the inspector’s ability to detect variations in the surface condition, such as cracks, corrosion, or other signs of wear without altering or damaging the material being inspected.

Visual inspection is fundamental in non-destructive testing because it serves as the first line of defense in identifying potential failures in materials and components. It is often a prerequisite before applying more sophisticated testing methods since inspectors can often spot obvious issues that might require further investigation using more advanced techniques.

While other methods such as magnetic inspection, liquid penetrant testing, and radiography are important for specific applications and can provide critical information about subsurface or internal defects, they do not serve the same purpose of direct observation as visual inspection does.