Methodology – Non Destructive Testing by Liquid penetrants


PMC ndt system

P-Met High-Tech Co. Pvt. Ltd. supplies PMC Liquid Penetrant Products Inspection System either of bench size or of large size of continuous automatic movement or hand operated movement. They are tailor made to meet the customers’ needs.

Surface Preparation of Test Specimen

Surface to be tested should be free from foreign matter which prevents penetration
Dust and dirt can be removed by a piece of cloth
Rust, paint, wax etc. to be removed from the testing surface bywire brush
Grease, oil etc. to be removed from the surface using PMC Cleaner

Application of Penetrant

Apply PMC Penetrant, by dipping, spraying or brushing, taking care that all surface areas are adequately covered.
A 5 to 10 minutes time is sufficient ( penetrant dwell time ) for penetration into defects. However, optimum period could be determined by trial only.

Removal of Excess Penetrant from the Testing Surface

The excess penetrant can be removed from the testing surface with a piece of clean cloth or absorbent paper
To remove excess penetrant from test surface in special cases”Use water spray if penetrant is water washable type”Use cloth or absorbent paper moistened with solvent if penetrant has solvent removable base”Use emulsifier for emulsifying penetrant and water spray if its a post-emulsifying penetrant
Take care to minimize removal of penetrant from the

Application of Developer


The Developer shall be applied as soon as possible, after removal of excess penetrant from the test surface. “With color contrast penetrant, only wet developer shall be used “With fluorescent penetrant, a wet or dry developer may be used. Ensure that the coating thickness is not insufficient or excessive to affect the defect indications.

Inspection of Testing Surface

The inspection of testing surface for discontinuity could be done in-“daylight, if visible color contrast red or pink penetrant is used”black light, if fluorescent penetrant is used.