3
Introduction to Visual Testing
3. Details become more visible when a contrast is established by:
l Differences in reflectivity.
l Color differences or discoloration.
l Casting shadows.
4. The types of details that can be detected by VT are:
l Discontinuities such as cracks and voids.
l Shape deviations such as excessive reinforcement of welds.
l Surface roughness or surface patterns.
5. Visual testing can be a very simple but powerful application.
6. One limitation of VT is that very tight cracks cannot be seen visually, requiring the application of other
NDT methods, such as magnetic particle testing (MT) or liquid penetrant testing (PT).
7. Another limitation is that non-surface-breaking discontinuities cannot be found by VT.
8. Normally, VT must be done by a Level II rather than a Level I individual because performance of VT
inspection and evaluation often cannot be separated.
Introduction to Visual Testing
3. Details become more visible when a contrast is established by:
l Differences in reflectivity.
l Color differences or discoloration.
l Casting shadows.
4. The types of details that can be detected by VT are:
l Discontinuities such as cracks and voids.
l Shape deviations such as excessive reinforcement of welds.
l Surface roughness or surface patterns.
5. Visual testing can be a very simple but powerful application.
6. One limitation of VT is that very tight cracks cannot be seen visually, requiring the application of other
NDT methods, such as magnetic particle testing (MT) or liquid penetrant testing (PT).
7. Another limitation is that non-surface-breaking discontinuities cannot be found by VT.
8. Normally, VT must be done by a Level II rather than a Level I individual because performance of VT
inspection and evaluation often cannot be separated.