Bleeding control

Penetrant examination is a method of non-destructive testing which extends visual inspection. It consists in applying to the surface to be inspected previously cleaned and dried, an impregnating liquid colored or fluorescent. The liquid enters, in particular by capillarity, in the openings of the defects.
After a time corresponding to the penetration of the impregnating liquid in the defects, the excess liquid present on the surface of the workpiece is removed by washing. The surface is then dried and coated with a developer that the impregnating liquid attracting retained in defects gives an indication thereof enhanced.
This method is used for finding surface defects leading to colored products under white light and fluorescent under ultraviolet light, a replica of the detected defects, etc..
It is reserved in principle control materials or porous or too rough, hence the importance of the surface of the test piece.
method:

• Apply a penetrant (liquid containing colored or fluorescent tracers with the property spread well on the surface and penetrate into the smallest discontinuities);
• Rinse the surface of the tracer;
• Apply a developer (micronized powder whose role is to absorb by capillarity discontinuities in entering content and provide a contrasting background).

After a time the penetrant diffusion, there are surface indications.
Some special products can meet the operational requirement of temperature parts.

We use this technique in the following ways:

• Chain manual bleed (colored or fluorescent products);
• Products in aerosol or bulk.