Advantages of the penetrant method of Non-Destructive Examination are:
- It is a very sensitive method, capable of finding extremely fine flaws
- It can be used on magnetic and non-magnetic metals, some plastics and glass
- Small objects, with awkward shapes, can be inspected
- A power supply is not needed for some methods of penetrant testing
- The method requires no great skill and is easy to understand
- Lots of small articles, in batches, can be examined using automated systems
Disadvantages of the penetrant method of Non-Destructive Examination are:
- Can only detect defects open to the surface
- Preparation, before testing, can be time consuming and costly
- The method takes time and can rarely be completed in less than 30 minutes
- The method cannot normally be applied to painted objects
- It is messy
- Interpretation of results is sometimes difficult
- There may be a problem disposing of contaminated cleaning and penetrant fluids
- Dry, clean, conditions are essential, as is careful cleaning of the surfaces to be examined
- The method is often abused and skimped, or not fully understood
- There can be a fume exposure problem, particularly in confined spaces
Books on the subject are:
- R Hamshaw, Introduction to the Non-Destructive Testing of Welded Joints, 2nd edition, Abington Publishing, Cambridge, UK, 1996 (ISBN 1 85573 314 5)
- David Lovejoy, Penetrant Examination. A Practical Guide, published by Chapman and Hall, 1991
- C E Betz, Principles of Penetrants, published by the Magnaflux Corporation, 1963
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