Liquid Penetrant Testing

Liquid Penetrant Testing LPI is widely applied as low cost inspection method used to locate surface breaking defects in all non-ferrous materials and ferrous materials; although for ferrous components magnetic particle inspection is often used. LPI is used to detect casting, forging & welding surface defects such as hairline cracks, surface porosity, leaks in new products and fatigue cracks on in-service components. We offer on-site liquid penetrant testing services using contrast or fluorescent penetrant for highly sensitive inspection. We offer on-site liquid penetrant inspection services. For detecting of surface breaking cracks in non-magnetic materials, we use both colour contrast and fluorescent penetrant for highly sensitive inspection.


  • It is used to inspect metals for surface defects
  • Weld discontinuities open to surface i.e. cracks, porosity and seams


  • It can be used on a wide variety of materials: ferrous and nonferrous metals and alloys, fired ceramics, powdered-metal products, glass, and some types of organic materials
  • Portable, relatively inexpensive equipment
  • Expedient inspection results
  • Results are easily interpreted
  • Requires no electrical energy except for light source
  • Indications may be further examined visually
  • Adapted to volume processing permitted 100 percent surface inspection


  • Surface films such as coatings, scale, and smeared metal mask or hide rejectable defects
  • Parts should be clean before and after inspection
  • Bleed out from porous surfaces can also mask indications
  • Remain in contact with body surfaces for extended periods, they may cause skin irritation