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warm lubricating oil, Specification MIL-L-6082.
Bearings preserved in oil
require no depreservation prior to use.
7.4
Fluorescent-Penetrant Method of Inspection (Zyglo)
7.5
General.
Inspection by the fluorescent-pcnetrant method, Specification MIL-I-6866,
is a nondestructive means of testing nonferrous part. for cracks and defects
that have openings to the surface.
A highly fluorescent, water-emulsifying,
low-viscosity oil is applied to a completely clean surface, and allowed to
penetrate any flaws.
The surface oil is then removed.
The residual oil
which has penetrated the flaw- glows when exposed to ultraviolet light,
thus revealing the extent of the defects.
7.6
Cleaning Prior to Application of Fluorescent-Penetrant
P
sure surfaces to be inspected are free of foreign
materials
(such
as heavy oil, grease,
rust, or scale)
which would either prevent penetration
of the oil, or indicate false flaws by absorbing the penetrant.
Polishing
61
causes false indications because displaced surface metal can cover defects
and thereby close the surface openings of deeper flaws.
Remove heavy oils
by degreasing, and remove dirt and scale by the applicable cleaning method.
7.7
Application of Fluorescent-Penetrant Oil
Apply the fluorescent-penetrant oil by immersing the part, or by flow.ing
the oil over it.
Allow approximately one hour for the oil to penetrate into
the surface openings.
Immerse in the emulsifier and drain 3 to 5 minutes.
Apply a warm-water spray to remove excess oil from the part, so that only
the oil which has penetrated deeply into the flaws remains.
Dry the part
in a soft flow of warm, dry air.
2
7.8
Application of Developer
After all excess fluorescent oil has been removed, cover the part with
11-7.3
5-
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