Non-Destructive Testing (NDT) Practice Test

What advantage does liquid penetrant testing have over an unaided visual inspection?

1. It requires less time

2. It allows detection of deeper flaws

3. It makes defects easier to see for the inspector

4. It is less expensive

The correct answer is: It makes defects easier to see for the inspector

Liquid penetrant testing offers significant advantages over unaided visual inspection, particularly in the way it enhances the visibility of surface defects. While visual inspection relies solely on the inspector's ability to see flaws with the naked eye, liquid penetrant testing involves applying a dye or fluorescent liquid to the surface of an object. This penetrant seeps into any surface-breaking defects, such as cracks or porosity. Once the excess penetrant is removed and a developer is applied, it draws the penetrant out of these defects, causing them to become visible as colored indications on the surface. This process significantly aids the inspector by improving the contrast and visibility of defects that may be very small or faint, which might not be easily noticeable during a visual inspection alone. While factors like time efficiency, the ability to detect deeper flaws, or costs can vary based on the specific context of the inspection, the primary advantage of liquid penetrant testing lies in its ability to make defects more visible, thereby enhancing the reliability of the inspection results.