Liquid Penetrant Testing (PT)


Liquid Penetrant testing, sometimes simply referred to as Penetrant Testing (PT),  is one of the most reliable methods when seeking to detect discontinuities open to the surface on a wide array of materials. PT is capable of detecting several different types of surface defects in non-porous materials. When performed in accordance with a properly prepared procedure, liquid penetrant is capable of detecting very fine surface discontinuities not visible to the naked eye. Relative to other methods, PT is fairly easy to use and can be used on a wide variety of materials.

The method is fairly easy to perform and consists of several main steps. The first step involves preparing the surface to be examined by cleaning it of any grease, oil, water, or other contaminants. Step two involves applying the penetrant to the material via either spraying, brushing, immersion, or flowing. The penetrant must then be allowed to dwell for a prescribed amount of time so that it is able to penetrate into a defect. The time required depends on several factors, such as, the type of penetrant used, the material being examined, the type of flaw being sought and the temperature of the item. Dwell times  may range from five minutes to an hour. The next step involves simply removing any excess penetrant from the surface; taking care to remove as little as possible from any possible defects. Different methods for removal exist based on the item being examined and type of penetrant. Next a thin layer of developer is applied, this draws the remaining penetrant out of the flaws which can then be inspected visually. Once the inspection is done, the final step is to clean the penetrant processing materials from the component.

Hi-Tech Testing utilizes both visible (color-contrast) and fluorescent dyes as the application dictates. Based upon other factors, the penetrant may be either solvent removable or water washable. We have the equipment, procedures and qualified technicians to meet both your needs and all code, standard, or specification requirements.

Contact Our PT Experts »