Liquid Penetrant Inspection

Liquid Penetrant Testing:

Liquid penetrant examination is one of the most popular Nondestructive Examination (NDE) methods in the industry. It is economical, versatile, and requires minimal training when compared to other NDE methods. Liquid penetrant exams check for material flaws open to the surface by flowing very thin liquid into the flaw and then drawing the liquid out with a chalk-like developer. Welds are the most common item inspected, but plate, bars, pipes, castings, and forgings are also commonly inspected using liquid penetrant examination.

Liquid penetrant testing

Over the years, liquid penetrant examination has been called many names: penetrant testing (PT), liquid penetrant testing (LP), and dye penetrant testing (DP). The American Society for Nondestructive Testing (ASNT) uses the name liquid penetrant testing (PT). The American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME B & PVC) and the National Board Inspection Code (NBIC) use the name liquid penetrant examination (PT).

The first documented use of PT was in the railroad industry. Cast railroad wheels were dipped in used oil, dried off, and then coated with powder chalk or suspension of chalk in alcohol. Once the wheels were dry, any oil stored in the flaw would bleed out into the chalk and be detected. This was called the oil and whiting method.

The dye penetrant solvent removable method is most popular because it is low cost and very versatile. It typically comes in three aerosol cans - cleaner, penetrant, and developer. The aerosol cans are very versatile which allow them to be taken up ladders, inside boilers, down into pits, and into very tight places. Most nonporous materials (steel, stainless steel, cast iron, aluminum, brass, bronze, titanium, rubber, plastics, and glass) can be examined using PT.

CCI provides a full range of economical liquid penetrant services. Whether it's high-volume production or testing individual, large, and complex objects, we offer quick turn-around and a high degree of reliability.