TM5-3810-305-10
8. There are different types of wearing of wire
rope (Figure 4-5 1):
a.
b.
c.
d.
From excessive bending (A).
Localized wear brought about by poor cut-
off practice (B).
Rope slides over or against itself (C).
Flexing the rope exposes broken wires
hidden in valleys between strands. This is
known as valley-type fatigue breaks (D).
B
c
D
Figure 4-51. Wearing of Wire Ropes
Rope Inspection Summary
Any wire rope that has broken wires, deformed
strands, variations in diameter or any change
from its normal appearance must be considered
for replacement. It is always better to replace a
rope when there is any doubt concerning its
condition or its ability to perform the required
task. The cost of wire rope replacement is quite
insignificant when considered in terms of injuries
to personnel, the cost of down time or the cost of
replacing broken structures.
Wire rope inspection includes examination of
basic items such as:
1. Rope diameter reduction.
2. Rope lay.
3. External wear.
4. Internal wear.
5. Peening.
6. Scrubbing.
7. Corrosion.
8. Broken wires.
Some sections of rope can breakup without any
prior warning. Already discussed in some detail
as to cause and effect, sections where this occurs
are ordinarily found at the end fittings, and at the
point where the rope enters or leaves the sheave
groove of boom hoists, suspension systems or
other semi-operational systems. Because of the
“working” that takes place at these sections, no
appreciable wear or crown breaks will appear.
Under such an operation, the core fails thereby
allowing the strands to notch adjacent strands.
However, when this happens, valley breaks will
appear. As soon as the first valley break is
detected, the rope should be removed immedi-
ately.
If preventive maintenance, previously described,
is diligently performed, the rope life will be
prolonged and the operation will be safer. Cut-
ting off a given length of rope at the end attach-
ment before the core deteriorates and valley
breaks appear, effectively eliminates these
sections as a source of danger.
4-5
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