Liquid Penetrant Testing (LPT) is one of the most widely used nondestructive evaluation (NDE) methods. Its popularity can be attributed to two main factors: its relative ease of use and its flexibility. LPT can be used to inspect almost any material provided that its surface is not extremely rough or porous.
Materials that are commonly inspected using LPT include the following:
- Metals (aluminum, copper, steel, titanium, etc.)
- Glass
- Many ceramic materials
- Rubber
- Plastics
Liquid penetrant inspection can only be used to inspect for flaws that break the surface of the sample such as,
- Fatigue cracks
- Quench cracks
- Grinding cracks
- Overload and impact fractures
- Porosity
- Laps
- Seams
- Pin holes in welds
- Lack of fusion or braising along the edge of the bond line
