Visual inspection is a non-destructive testing (NDT) method whereby individuals look for defects that can be seen with the eye, or equipment that slightly enhances the area being looked at. This type of inspection is frequently used, but infrequently used alone because of its capabilities. If you want to know whether visual inspection is an effective NDT method, then read all about it below:
Visual inspection is an NDT method that can be used to inspect the surface of a material; however, regardless of how skilled the analyst is, it is incredibly difficult to notice a minute defect by using only visual inspection. The best time to use visual inspection would be to monitor an existing crack or to perform basic inspections in order to identify visible cracks and discontinuities.
When performing visual inspections, analysts will usually make use of a magnifying glass, microscope, or other visually enhancing equipment. Unfortunately, none of the equipment used for visual inspection can be used to detect defects below the surface of the material. If the material has been coated, it would need to be stripped before visual inspection can take place.
This NDT method is much less expensive than others as it does not require as much training and the equipment is not expensive to run; however, there is a high-risk of missing flaws which can develop into seriously expensive problems. This is why visual inspection should not be conducted as the sole NDT method, but it may be effective when used alongside other NDT methods.