TM 55-2840-254-23
GLOSSARY (Continued)
Definition
P
Parent Metal . . . . . . . . . . . . . . . . . . . . . . . . . The basic metal of a part, sometimes referred to as base
metal; the term is used particularly in connection with weld-
ing, where the parent metal is that being welded rather than
that used in welding rod.
Peening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surface deformation.
Phenolic. . . . . . . . . . . . . . . . . . . . . . . . . . . . A thermosetting resin or plastic made especially for molding
and insulating, coatings and adhesives.
Pitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Very shallow depressions in a surface, usually caused by
chemical reaction (rusting chemical corrosion).
Popping . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sharp abrupt noise normally caused by erratic bleed band
operation.
Protrusion . . . . . . . . . . . . . . . . . . . . . . . . . . Projection sticking out from the rest of the surrounding
material or surface.
Puncture . . . . . . . . . . . . . . . . . .
.......
A hole that is pierced in a material.
R
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . .
To restore a defective part, component, subassembly or as-
sembly to a serviceable condition.
Rollover . . . . . . . . . . . . . . . . . . .
.......
A curl usually on the leading edge of a blade, resulting from
deformation by the peening action of foreign objects.
Rub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . When one component contacts another and is moved in rela-
tionship to it causing material to be removed from it.
Rust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oxidation of iron. A red, crusty product which forms on
iron or steel when it unites with oxygen.
S
Scoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multiple scratches, usually parallel and resulting from the
same cause.
Scratch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A long, narrow sharp-cornered impression caused by the
movement of a sharp object across the surface of parent
material.
Glossary-4
