PT
penetrant testing
The most universal type of surface testing for detecting material discontinuities open towards the surface. Contrary to magnetic particle testing, penetration testing can be applied to elements basically regardless of the type of material.
Non-destructive penetration testing allows the detection of discontinuities that are open to the material surface. It is a very common method because it is easy to carry out. By using the capillary phenomenon, consisting in the penetration and uplift of the liquid, one can see very narrow cracks on the surface of the material after the liquid is colored. The test surface must be clean, free from any contamination. In contrast to magnetic particle testing, penetrant testing can be used to test various elements basically regardless of the type of material. However, if any discontinuities in the material reaching the surface "are closed" will not be detected.