LIQUID
(DYE) PENETRANT
The first of the surface methods is Liquid Penetrant Inspection. This method is used to detect surface breakage and can be used on any material. Dye penetrant is most frequently used if the material is non-magnetic. The test object is thoroughly cleaned then coated with a solution that contains either a visible (colored) or fluorescent dye.
After sufficient time has elapsed for the liquid to be drawn into any cracks,
the excess solution is removed from the surface of the object, leaving the
dye in surface breaking defects. A second liquid, known as a developer, is
then applied to draw the penetrant out of the defects making them visible.
Coloured penetrants require adequate white light to be visible, while fluorescent
dyes require a darkened room with the inspected part illuminated by ultraviolet
light making the bleedout fluoresce brightly, thus allowing imperfections
to be readily seen. The red indications in the photograph represent a number
of defects in this component.
The first of the surface methods is Liquid Penetrant Inspection. This method is used to detect surface breakage and can be used on any material. Dye penetrant is most frequently used if the material is non-magnetic. The test object is thoroughly cleaned then coated with a solution that contains either a visible (colored) or fluorescent dye.
After sufficient time has elapsed for the liquid to be drawn into any cracks,
the excess solution is removed from the surface of the object, leaving the
dye in surface breaking defects. A second liquid, known as a developer, is
then applied to draw the penetrant out of the defects making them visible.
Coloured penetrants require adequate white light to be visible, while fluorescent
dyes require a darkened room with the inspected part illuminated by ultraviolet
light making the bleedout fluoresce brightly, thus allowing imperfections
to be readily seen. The red indications in the photograph represent a number
of defects in this component.
