Liquid Penetrant Testing
Detecting Flaws on Non-porous Surfaces
Liquid penetrant testing is also known as liquid penetrant inspection, dye penetrant testing, penetrant testing or LPI. This test method is reliable for detecting surface-breaking flaws in materials with a non-porous surface such as metals, plastics, glass and ceramics.
NDT penetrant testing relies on a fluorescent or visible dye penetrant seeping into a flaw such as a lap, seam, fracture or crack. This forms a surface indication that can be evaluated under special lighting.
Penetrant Testing to Meet Your Requirements
Laboratory Testing Inc. is Nadcap accredited for liquid penetrant inspection and provides a certified test report with each order. The Lab is located in the Philadelphia, PA (USA) area and also offers the following:
- Fluorescent and Visible Dye Penetrant Testing
- Orders are processed with the highest quality Magnaflux testing materials
- Water-washable and post-emulsifiable fluorescent penetrants in sensitivity levels 2, 3 and 4 are available to meet your specification or application
- Certified NDT technicians:
- ASNT SNT-TC-1A
- Pratt & Whitney PWA-NDTQ
- Testing for products up to 25 ft. in length
- ASTM E1417
The Liquid Penetrant Testing Process
Before performing a liquid penetrant test, the surface of the test material must be thoroughly cleaned to remove any contaminants that could prevent the penetrant from entering flaws. Etching may be required if mechanical operations such as machining, sanding, or grit blasting have been performed on the item.
A fluorescent or red visible dye penetrant is applied to the cleaned test material, then it is left on the surface for a sufficient time to allow penetrant to seep into a defect. After this dwell time has elapsed, the excess penetrant is removed from the surface. Next, a thin layer of developer is applied to the item to assist in drawing penetrant trapped in flaws back to the surface where it will be visible as indications. The test item is viewed under special lighting so any indications can be evaluated according to the liquid penetrant testing specification or customer requirements. When performing fluorescent penetrant testing, indications must be viewed under darkened conditions with a high-intensity UV lamp.
LTI’s equipment includes three large liquid penetrant testing dip tanks, a 25 ft. dwell tank for pipe, tubing, bar, etc. and a large testing room with three high-intensity black lights.
Read a full description of the Penetrant Testing process.
- Dye Penetrants – Magnaflux brand
- Visible dye
- Fluorescent – water-washable and post-emulsifiable penetrants in sensitivity levels 2, 3 and 4
- Products Tested – metals and other non-porous materials
- Size Availability – ability to test materials up to 25 feet long
- Certified NDT Level 2 and Level 3 Inspectors – evaluate all test results