Penetrant Testing PT ：
a. Purpose: Detecting the surface-breaking discontinuities of wide variety non-porous materials.
b. Principle and dye penetrant process:
Liquid penetrant testing is based upon capillary action, where low surface tension fluid penetrates clean and dry surface-breaking discontinuities. and excess surface penetrant is then removed; a developer (typically a dry powder) is then applied to the surface, to draw out the penetrant in the crack and produce a surface indication.
1) Color contrast penetrant :
2) Fluorescent penetrant :
c. Application:
1) Ferrous and non-ferrous metals and alloys.
2) Aerospace parts.
3) Turbine blades and shafts
4).Structural and piping weld joints.
5) Tube sheet
