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What are the advantages and disadvantages of penetrant examination in Non-Destructive Examination (NDE)?


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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