Full Transcript:

What’s up guys?!?!?!?! This is Michael back for more metals madness today. We’re still talkin testin so let’s jump in.

Our topic today is another of the inspection methods that can be used to check a metal part for defects without damaging the component being examined.

Liquid Penetrant Testing  ….LP for short; is one of several methods of non destructive testing used to detect surface defects.  This technique does not work for defects that are not open to the surface.

Surface defects in metals can often be difficult to see in a visual examination.

So what can we do to see a defect more clearly?

To enhance the visibility of a defect, we can apply a low surface tension liquid to a clean part surface. If there is an open surface defect present, the liquid is drawn into it by the surface tension. Excess penetrant is removed and in most cases a developer is applied to further enhance the visibility of the penetrant remaining in the defect.

Either the penetrant or the developer can carry a dye that is visible under ordinary intense light or fluorescent under ultraviolet light.

Clean surfaces are critical to allow the surface tension and wetting of the surface do their job in flowing into the defect.

Depending on Inspection requirements, the surface finish is also a consideration. Rough machined surfaces may not be suitable for producing an acceptable test result; defects could be hidden by the machined texture of the surface.

All Non Destructive Evaluation ( NDE) is intended to confirm the quality of a part and requires careful planning.  Many parts require inspections at multiple steps in fabrication.

If you are a regular viewer of our video series, then you know that  things can get very complicated in a hurry. So  for time one hundred and eight, don’t forget toooooo  CHECK THE SPECS  !!!!!!!!

Thanks for watching, this is Michael with Michael Talks Metal, if you made it this far and haven’t subscribed please click here. If you missed last weeks video, please click here. Michlin is a distributor of all things metal, check the website for more info www.michlinmetals.com, See you all next Thursday 10am. Same time, same place, I’m out!