Penetrant testing (PT) is the inspection method that can detect the discontinuities on the surface such as cracks, porosity, incomplete fusion, and flaws in joints. This method is based on the capillary action where the liquid is drawn into the clean and dry surface discontinuities.
Penetrant Testing Processes
When performing the test, the part needs to be cleaned thoroughly, then the penetrant liquid is applied on the part. The excess penetrant has to be removed from the surface, after that developer will be applied on the surface in order to draw the penetrant liquid to the surface discontinuities. Then the inspectors will evaluate the results.
Advantages of Penetrant Testing Method
Can detect small discontinuities
Can be inspected in many materials and shapes
Fast
Low cost
Simple
Limitation of Penetrant Testing Method
Can only detect discontinuities that are opened to the surface
Inspected parts need to be cleaned properly
All the processes need to be done correctly
Interpretation sometimes can be tricky
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