The choice of penetrant in PT primarily depends on which of the following?

The selection of a penetrant in Liquid Penetrant Testing (PT) is fundamentally influenced by the defect size and type of material being inspected. Different materials can have varying surface conditions, porosity, and chemical compositions, which can affect how well a penetrant can penetrate, remain in flaws, or be washed off.

For instance, non-porous materials might require a different type of penetrant compared to porous ones, as the latter can trap the penetrant more effectively. Furthermore, the size of the defect is critical; small cracks may require a low-viscosity penetrant that can seep into tiny gaps, while larger defects might be effectively detected with a different formulation.

Considering these aspects ensures that the chosen penetrant can effectively enhance the visibility of the indications, thereby improving the reliability of the testing process. In summary, the interplay between material characteristics and defect dimensions significantly dictates the appropriate penetrant choice for optimal testing results.