IWRC or strand core protrusion between outer strands, commonly called bird
caging or popped core, usually results from shock loading during operation, but
can also be caused by improper handling. The damage is irreparable and the
affected area must
be
cut out or the entire rope taken out
of
service.
Crushing or flattening
of
the strands or rope is caused
by
various factors,
including poor spooling on a drum, heavy loading and even poor installation
procedures. This can result in broken wires or the accelerated deterioration
of
the
rope.
Abrasion (metal loss) and peening (metal deformation) occur when the rope
contacts another metallic
or
abrasive surface, or from passing over the drum or
sheaves. These result in the reduction
of
diameter and broken wires.
Corrosion is most often the result
of
a lack
of
lubrication. It may result in pre-
mature fatigue failure
of
individual wires.
It
is especially important to inspect
ropes at end terminations.
Heat damage comes from any heat source such as welding, fire, power line
strikes, or lightning. The damage is irreparable and the affected area must be cut
out or the entire rope taken out
of
service.
Protruding broken wire
is
a condition where one outer wire is broken at the
point
of
contact with the core
of
the rope and has worked its way out
of
the rope
structure and protrudes or loops out from the rope structure. The damage
is
irreparable and the affected area must be cut out
or
the entire rope taken out
of
service. There are occasions when a valley break (at strand to strand contact
point) will protrude
or
raise above the surface
of
the rope. This also is a condi-
tion
of
serious concern and somewhat difficult to differentiate from a wire break
at the strand to core contact point. When there are two or more valley breaks
in
a
rope lay the affected area must be cut out or the rope taken out
of
service.
INSPECTION RECORDS
Periodic inspections require a permanent record
of
each rope on the equip-
ment. The sample form included in this brochure may be copied and completed
by the inspector for the permanent record. This form
is
designed to provide a
road map for recording pertinent data as an inspection proceeds.
Any wire rope manufacturer that
is
a member
of
the Wire Rope Technical
Board can provide inspection criteria, including recommendations and require-
ments
of
OSHA, ASME, ANSI, and other industry and governmental regulations.
Permanent records
of
inspections are required by OSHA and other governmen-
tal regulations, and will be used
for reference at the next inspection. These can
be kept with the operator and maintenance manuals for the application, or in
per-
manent office files.
72 • Wire Rope Technical Board - Wire Rope Users Manual, Fourth Edition
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