Penetrant Testing – PT

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Penetrant testing is a non-destructive testing method used to detect casting, forging, and welding surface defects such as hairline cracks, surface porosity, leaks in new products, fatigue cracks on in-service components, and locate surface breaking discontinuities in non-porous materials (metals, plastics, or ceramics). This method may be applied to ferrous and non-ferrous materials, although for ferrous components magnetic-particle testing is often used instead for its subsurface detection capability.


  • Welds and weld overlays, castings and forgings, valves and their components, machined parts, pressure vessels, clad vessel linings, and structural steel
  • New fabrication weld inspection
  • Code compliant inspection
  • In-service welds
  • Ferrous and non-ferrous components


  • High visibility of indications
  • Low cost and fast results
  • Field Ready
  • Highly portable tools can be used in most locations
  • Can operate with battery power as well as supplied power


  • Can only detect surface flaws
  • Conducting the test on rough surfaces, such as as-fabricated welds, will make it difficult to remove any excessive penetrant and could result in false indications
  • Penetrants are limited by temperature and generally operate best in the range of 4 °C to 52 °C (40 °F to 125 °F); special procedure and penetrants can be used for temperatures outside this range but these must be qualified by a procedure test
  • Test material must be relatively non-porous