wire rope - naarso . wire rope is an intricate device made up of a number of precise moving parts....
TRANSCRIPT
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Wire rope is an intricate device made up of a number of precise moving parts.
The moving parts of wire rope are designed and manufactured to maintain
a definite relationship with one another. This relationship ensures that the wire rope
has the flexibility and strength crucial to professional
and safe hoisting operations.
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Wire Rope
• Wire ropes are manufactured in a great variety of constructions to meet the varying
demands of usage. – Where abrasion is an important factor the rope
must be made of course construction with relatively large wire.
– Where flexibility is the issue because the rope is subject to more bending the construction should
be of many smaller wires.
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WIRE ROPE SELECTION Several factors must be considered when you
select a wire rope for use in a particular type of operation.
Manufacture of a wire rope that can with stand all of the different types of wear
and stress, it is subjected to, is impossible.
Because of this factor, selecting a rope is often a matter of compromise.
You must sacrifice one quality to have some other more
urgently needed characteristic.
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WIRE ROPE CONSTRUCTION
Wire rope is composed of three parts: 1. WIRES 2. STRANDS 3. CORE
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A predetermined number of WIRES
of the same or different size
are fabricated in a uniform arrangement of definite lay
to form a STRAND.
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The required number of strands
is then laid together symmetrically around the
CORE to form the wire rope.
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Wires The basic component of the wire rope is the wire.
The wire may be made of steel, iron, or other metal in various sizes.
The number of wires to a strand varies, depending on what purpose the wire rope is intended. Wire rope is designated by the number of strands per
rope and the number of wires per strand. Thus a 1/2-inch 6 by 19 wire rope has six strands with
19 wires per strand. It has the same outside diameter
as a 1/2-inch 6 by 37 wire rope that has six strands with 37 wires (of smaller size) per strand.
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Thus a 1/2-inch
6 by 19 wire rope has six strands with 19 wires per strand.
It has the same outside diameter as a 1/2-inch 6 by 37 wire rope
that has six strands with 37 wires
(of smaller size) per strand.
19
37
6
6
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Strands The design arrangement of a strand is called the construction.
The wires in the strand may be all the same size or a mixture of sizes.
The most common strand constructions are 1. Ordinary, 2. Scale, 3. Warrington, 4. Filler.
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Ordinary construction wires are all the same
size.
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Scale is where larger diameter wires
are used on the outside of the strand to
resist abrasion and smaller wires are inside
to provide flexibility.
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Warrington is where alternate wires
are large and small to combine great flexibility with
resistance to abrasion.
Filler is where small wires
fill in the valleys between the outer and inner rows of wires
to provide good abrasion and fatigue resistance.
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Core
The wire rope core supports the strands laid around it.
The three types of wire rope cores are fiber,
wire strand, and independent wire rope.
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A fiber core maybe a hard fiber, such as manila,
hemp, plastic, paper,
or sisal. Sisal (Agave sisalana)
is an agave that yields a stiff fiber
traditionally used in making twine, rope and also dartboards. The fiber core offers the advantage of increased flexibility.
It also serves as a cushion to reduce the effects of sudden strain and act as
an oil reservoir to lubricate the wire and strands (to reduce friction).
Wire rope with a fiber core is used when flexibility of the rope is important.
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A wire strand core resists more heat than a fiber core and
also adds about 15 percent to the strength of the rope;
however, the wire strand core
makes the wire rope less flexible than a fiber core.
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An independent wire rope core is a separate wire rope
over which the main strands of the rope are laid. This core strengthens the rope,
provides support against crushing,
and supplies maximum resistance to heat
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Ordinary lay The lay of wires in each strand is in the opposite direction to the lay of the strands that form the wire.
Lang's lay The lay of wires in each strand is in the same direction as the lay of the strands that form the wire.
Alternate lay
The lay of wires in the strands alternate around the rope between being in the opposite and same direction to the lay of the strands that form the wire rope.
Regular lay Alternate term for ordinary lay.
Albert's lay Archaic term for Lang's lay.
Reverse lay Alternate term for alternate lay.
Spring lay This is not a term used to classify a lay as defined in this section. It refers to a specific construction type of wire rope.
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6x19 FC RH OL FSWR
6 Number of strands that make up the rope
19 Number of wires that make up each strand
FC Fibre core
RH Right hand lay
OL Ordinary lay
FSWR Flexible steel wire rope
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Abbr. Description
FC Fibre core
FSWR Flexible steel wire rope
FW Filler wire
IWR Independent wire rope
IWRC Independent wire rope core
J Jute (fibre)
LH Left hand lay
LL Lang's lay
NR Non-rotating
WIRE TERMS
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OL Ordinary lay
RH Right hand lay
S Seale
SF Seale filler wire
SW Seale Warrington
SWL Safe working load
TS Triangular strand
W Warrington
WF Warriflex
WLL Working load limit
WS Warrington Seale
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Regular Lay
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Left-hand ordinary lay (LHOL) wire rope (close-up). Right-hand lay strands are laid into a left-hand lay
rope.
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Right-hand Lang's lay (RHLL) wire rope (close-up). Right-hand lay strands are laid into a right-hand lay
rope.
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Tensile Strength
TENSILE STRENGTH is the strength necessary to
WITHSTAND a certain maximum load applied to the rope.
It includes a reserve of strength measured in
a so-called factor of safety.
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Crushing Strength CRUSHING STRENGTH
is the strength necessary to RESIST THE compressive and squeezing forces
That distort the cross section of a wire rope, as it runs over sheaves, rollers,
and hoist drums when under a heavy load. Regular lay rope distorts less in these situations than lang
lay.
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Fatigue Resistance FATIGUE RESISTANCE
is the ability to WITHSTAND the constant bending and flexing
of wire rope that runs continuously on sheaves and hoist drums.
Fatigue resistance is important when the wire rope must be run at high speeds.
Such constant and rapid bending of the rope can break individual wires in the strands.
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LANG LAY ropes are best for service
requiring high fatigue resistance.
Ropes with smaller wires around the outside of their strands also have greater fatigue resistance,
since these strands are more flexible.
FATIGUE RESISTANCE
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Abrasion Resistance Abrasion resistance
is the ability to WITHSTAND the gradual wearing away of the outer metal,
as the rope runs across sheaves and hoist drums. The rate of abrasion depends
mainly on the load carried by the rope and the running speed.
Generally, abrasion resistance in a rope depends
on the type of metal that the rope is made of
and the size of the individual outer wires.
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Abrasion resistance
Wire rope made of the harder steels, such as improved PLOW STEEL,
has considerable resistance to abrasion. Ropes that have larger wires forming
the outside of their strands are more resistant to wear than
Ropes having smaller wires
that wear away more quickly.
plow steel n. A high-strength steel having a carbon content of 0.5 to 0.95 percent and used primarily to make wire rope.
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Corrosion Resistance Corrosion resistance is the ability to withstand the
dissolution of the wire metal that results from chemical attack by moisture in the atmosphere or
elsewhere in the working environment. Ropes that are
put to static work, such as guy wires, maybe protected
from corrosive elements by paint or other special dressings. Wire rope may also be galvanized for corrosion protection.
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WIRE ROPE
FAILURE 2/12/2015 49 N.A.A.R.S.O.
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Look close . Can you find what’s so important???????
abrasion 2/12/2015 56 N.A.A.R.S.O.
material fatigue
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Drum crushing is caused by small drums, high loads and multiple winding conditions.
A kinked wire rope is shown here. It's caused by pulling down a loop in a slack line during handling, installation or operation. Note the distortion of the strands and individual wires. This rope must be replaced
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Here's a wire rope that has jumped a sheave. The rope "curled"as it went over the edge of the sheave. When you study the wires, you'll see two types of breaks here: tensile "cup and cone" breaks and sheat breaks that appear to have been cut on an angle.
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A "birdcage" is caused by sudden release of tension and the resulting rebound of rope. These strands and wires will not be returned to their original positions. The rope should be replaced immediately.
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A wire rope that has been subjected to repeated bending over sheaves under normal loads. This results in fatigue breaks in individual wires -- these breaks are square and usually in the crown of the strands.
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An example of fatigue failure of a wire rope subjected to heavy loads over small sheaves. The breaks in the valleys of the strands are caused by "strand nicking." There may be crown breaks, too. 2/12/2015 60 N.A.A.R.S.O.
WHY ????
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WIRE ROPE FAILURE Some of the common causes of wire rope failure
are the following:
1.Using incorrect size 2.Construction or grade
3.Dragging over obstacles 4.Improper lubrication
5.Operating over sheaves and drums of inadequate size
6.Overriding or cross winding on drums
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7.Operating over sheaves and drums with improperly fitted grooves or
broken flanges 8.Jumping off sheaves
9.Exposure to acid fumes 10.Use of an improperly attached fitting
11.Grit being allowed to penetrate between the strands, causing internal wear
12.Being subjected to severe or continuing overload
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Kinks One of the most common types of damage
resulting from the improper handling of wire rope is the development of a kink.
A kink starts with the formation of a loop. A loop that has not been pulled tight enough to set the wires,
or strands, of the rope into a kink can be removed
by turning the rope at either end in the proper direction to restore the lay.
If this is not done and
the loop is pulled tight enough to cause a kink , the kink will result in
irreparable damage to the rope N.A.A.R.S.O. 2/12/2015
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This way to a kink
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Kinking can be prevented by proper uncoiling and unreeling methods and by the correct handling
of the rope throughout its installation.
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Reverse Bends Whenever possible,
drums, sheaves, and blocks used with wire rope should be placed to avoid
Reverse or S-shaped bends. Reverse bends cause the individual wires or
strands to shift too much and increase wear and fatigue.
For a reverse bend, the drums and
blocks affecting the reversal should be of a larger diameter than ordinarily used and
should be spaced as far apart as possible.
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INSPECTION Wire rope should be inspected at regular internals,
the same as fiber line. The frequency of inspection
is determined by the use of the rope and the conditions
under which it is used. Throughout an inspection,
the rope should be examined carefully for
fishhooks, kinks,
worn spots, Corroded spots.
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Usually breaks in individual wires will be concentrated in areas
where the wire runs continually over the sheaves or
bend onto the drum. Abrasion or
reverse and sharp bends cause individual wires to break and
bend back. These breaks are known as FISHHOOKS.
FISHHOOKS
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When wires are slightly worn but have broken off squarely and
stick out all over the rope, that condition is usually caused by overloading
or rough handling. If the breaks are confined to one or two strands,
then the strength of the rope maybe seriously reduced.
When 4 percent of the total number of wires in the rope are found to have
breaks within the length of one lay of the rope, the rope is considered unsafe.
Consider the rope unsafe when three broken wires are found in one strand
of 6 by 7 rope, six broken wires in one strand of 6 by 19 rope,
or nine broken wires in one strand of 6 by 37 rope.
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Usually caused by pulling down a loop or knot or jumping a sheave
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• Birdcage • Usually
caused by sudden release of load
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Ansi B30.5 N.A.A.R.S.O. 2/12/2015
Wire rope clamps/clips (aka "Crosby Clips" or "Dog Clamps") A wire rope clamp, also called a clip, is used to fix the loose end of the loop back to the wire rope. It usually consists of a u-shaped bolt, a forged saddle and two nuts. The two layers of wire rope are placed in the u-bolt. The saddle is then fitted over the ropes on to the bolt (the saddle includes two holes to fit to the u-bolt). The nuts secure the arrangement in place. Three or more clamps are usually used to terminate a wire rope. There is an old adage which has over time become the rule; when installing the three clamps to secure the loop at the end of your wire rope make sure you do not "Saddle a Dead Horse!" The saddle portion of the clamp assembly is placed and tightened on the opposite side of the terminal end of the cable. 2/12/2015 79 N.A.A.R.S.O.
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NEVER SADDLE A DEAD HORSE.
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Do you See
the # 1?
Stand off
Never touching
All running ropes in service should be visually inspected once each working day.
A visual inspection shall consist of observation of all rope which can reasonably be expected to
be in use during the day’s operations. These visual observations
should be concerned with discovering gross damage, such as listed below which may be an immediate hazard:
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[A] Distortion of the rope such as kinking, crushing,
unstranding, birdcaging,
main strand displacement, or core
protrusion. Loss of rope diameter in a short rope length or
unevenness of outer strands should provide evidence that the
rope must be replaced.
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[B] General Corrosion
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[C] Broken or Cut strands
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[D] Number, distribution,
and type of visible broken wires
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[E] Core failure in rotation resistant ropes: when such damage is discovered,
the rope shall be either removed from service or given an inspection
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The frequency of detailed and thorough inspections should be determined by a
qualified person, who takes into account the following factors:
• Expected rope life as determined by [a] maintenance records,
[b] experience on the particular installation or similar installations
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Severity of
environment
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Percentage of
capacity lifts
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Frequency rates of operation, And
exposure to shock loads
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Inspect the entire length of the rope. Some areas of the wire rope such as around the core
are more difficult to inspect. To inspect the core,
examine the rope as it passes over the sheaves. The strands have a tendency to open up slightly
which will afford the inspector a better view of the core. Also regularly inspect for any reduction in diameter
and lengthening of rope lay as both conditions indicate core damage.
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Basic Guidelines
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Abrasion Abrasion damage may occur when the rope contacts
an abrasive medium or simply when it passes over the drum and sheaves.
Therefore it is vital that all components be in proper working order and
of the appropriate diameter of the rope. A badly corrugated or
worn sheave or drum will seriously damage a new rope, resulting in premature rope replacement.
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Corrosion Corrosion is very difficult to evaluate but is a more serious cause of degradation than abrasion.
Usually signifying a lack of lubrication, corrosion will often occur internally
before there is any visible external evidence on the rope’s surface.
A slight discoloration caused by rusting Usually indicates a need for lubrication which should be tended to immediately.
If this condition persists, it will lead to severe corrosion
which promotes premature fatigue failures in the wires and strands,
necessitating the rope’s immediate removal from service.
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Wire Breaks The number of broken wires on the outside
of the wire rope is an indication of its general condition and whether or not it must be considered for replacement.
The inspector may use a type of spike to gently probe the strands
for any wire breaks that do not protrude. Check as the rope runs at a slow speed over the sheaves, where crown (surface) wire breaks may be easier to see.
Also examine the rope near the end connections. Replace the rope when the wire breaks
reach the total number allowable by ASME or other applicable specifications.
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Valley Breaks breaks in between strands,
must be taken very seriously at all times! When two or more valley breaks
are found in one lay-length, immediately replace the rope.
Valley breaks are difficult to see; however,
if you see one you can be assured that there are a few more hidden in the same area.
Crown breaks are signs of normal deterioration, but valley breaks indicate an abnormal condition
such as fatigue or breakage of other wires
such as those in the core.
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Once crown and valley breaks appear, their number will steadily and
quickly increase as time goes on. The broken wires should be removed as soon as possible
by bending the broken wire back and forth with a pair of pliers. In this way the wire is more likely to break inside the rope
where the ends will be tucked away.
If the broken wires are not removed they may cause further damage.
The inspector must obey the broken wire standard; pushing the rope for more life will create a dangerous situation.
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Diameter Reduction. Diameter reduction is critical deterioration
factor and can be caused by: • Excessive abrasion of the outside wires
• Loss of core diameter/support • Internal or external corrosion damage
• Inner wire failure • A lengthening of rope lay
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It is important to check and record a new rope’s actual diameter when under normal load conditions.
During the life of the rope the inspector should periodically measure
the actual diameter of the rope at the same location under equivalent loading conditions.
This procedure if followed carefully reveals a common rope characteristic— after an initial reduction,
the overall diameter will stabilize and slowly decrease in diameter during the course of the rope’s life.
This condition is normal.
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However, if diameter reduction is isolated to one area or happens quickly,
the inspector must immediately determine
(and correct, if necessary) the cause of the diameter loss,
and schedule the rope for replacement.
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Crushing. Crushing or flattening of the strands
can be caused by a number of different factors. These problems usually occur on multilayer spooling
conditions but can occur by simply using the wrong wire rope
construction. Most premature crushing and/or flattening conditions occur
because of improper installation of the wire rope.
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In many cases failure to obtain a very tight first layer (the foundation)
will cause loose or “gappy” conditions in the wire rope which will cause rapid deterioration.
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Failure to properly break- in the new rope,
or worse, to have no break-in procedure
at all, will cause similar poor spooling
conditions.
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Therefore, it is imperative
that the inspector knows how to
inspect the wire rope as well as how that rope
was installed.
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Shock loading. Shock loading (birdcaging) of the rope
is another reason for replacement of the rope. Shock loading is caused by the sudden release of
tension on the wire rope and
its resultant rebound from being overloaded. The damage that occurs can never be corrected
and the rope must be replaced.
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High Stranding. High stranding may occur
for a number of reasons such as failure to properly seize the rope prior
to installation or maintain seizing during wedge socket installation.
Sometimes wavy rope occurs due to kinks or
a very tight grooving problem.
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Another possibility is simply introducing torque or twist
into a new rope during poor installation procedures. This condition requires the inspector to evaluate
the continued use of the rope or increase the frequency of inspection
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Inspection Guidelines Specialty Ropes
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Plastic-Infused Rope. Plastic-infused rope was developed
to provide better fatigue, abrasion and
crushing resistance derived from the cushioning and dampening effect of the plastic.
However great the benefits, the plastic becomes at the very least an inconvenience
when trying to inspect the wire rope.
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Because of the plastic coating, some operators choose to forego inspection and
run the ropes to failure. Other operators may just visually inspect the plastic
coating. Both practices are wrong and
carry equally the potential for disaster.
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Abrasion and Crushing. In inspecting plastic-infused ropes,
the basic inspection guidelines still apply and Should be followed.
Abrasion and crushing damage may still occur, so it is imperative to inspect flanges,
sheaves, bearings,
rollers and fairleads.
Look for unusual wear patterns in the plastic-- a key indicator that damage to the wire rope
is occurring
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Wire Breaks. Wire breaks will still occur in a plastic infused rope,
but are sometimes extremely difficult to detect, though occasionally a broken wire will protrude through the plastic.
Every effort must be made to determine the overall condition of the rope. The plastic covering the crown (surface)
wires is generally applied in a thin coat and tends to wear quickly in areas which pass over sheaves and drums.
As the rope runs at a slow speed, inspect the rope in these areas. As the rope and plastic open up
the inspector will be afforded a look at not only the surface area but also the interstrand contact points.
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If a valley break is detected, Immediately pull the ropes from service.
Also inspect areas where plastic has peeled, regardless of the location of the “window.”
Remove as much plastic from these areas as possible
to allow for efficient and effective inspection techniques. Remember,
due to the nature of plastic-infused ropes, there is no way to clearly determine the number of
valley breaks.
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Corrosion. Plastic-infused ropes provide only improved corrosion
resistance. Regardless of manufacturers’ claims, a plastic-infused rope can corrode,
and rope failure due to corrosion is still possible. Moisture is sometimes trapped
in the rope and as with all machines,
the lubricant may become ineffective over time.
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The inspector must visually check for any signs of corrosion damage
as evidenced by rope bleeding or
rouging. In addition,
the diameter must be frequently measured. If there is any damage to the core,
it will be detected by a reduction in diameter.
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Also inspect the lay of the rope. As the plastic is thinner over the crown wires,
a thorough inspection may be able to determine a lengthening of lay,
also a sign of rope deterioration. Especially when trying to determine lengthening of lay,
watch for and inspect areas where the plastic pulls away from the rope.
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While peeling in and of itself is not an indication of rope deterioration
and is a factor of normal wear, Peeling
in areas where no abrasion exists may signify a problem.
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Maintenance Records. Equally important in inspecting plastic-infused ropes
is maintaining accurate service records. The service records of previous ropes
will provide a guideline as to the expected life of the rope. However,
they should not be used alone or only in conjunction with visual inspections due to the number of variables which exist,
including installation, spooling and
manufacturing practices.
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Maintenance records must be used in combination with both visual
and physical inspection techniques to be truly of value in
determining the remaining life of the rope.
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Compacted Rope. Die drawn and swaged ropes fall into the compacted
category. Compacting serves several purposes.
By flattening the outer wires, metallic area increases
allowing for a higher breaking strength as well as improved crushing and
abrasion resistance. In addition,
the compaction minimizes interstrand nicking and
thereby improves fatigue resistance.
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In the inspection of compacted rope designs, again it is imperative to follow the basic inspection
guidelines and use both visual and actual measuring techniques
to determine the remaining life of the rope. In fact,
actual measuring techniques are very important when inspecting these ropes.
While corrosion is relatively easy to visually determine,
diameter reduction may not be due to the compacted rope’s appearance.
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Therefore the inspector must regularly measure for diameter reduction and closely
examine the rope for lay lengthening. Measurements must be recorded and
the rope monitored for sudden variations.
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By and large the most difficult retirement criteria to determine in compacted ropes is wire breaks.
These breaks may not protrude from the rope due to the compaction and can be easily overlooked.
Because of this, the inspector must slowly and carefully examine the rope,
especially in those areas passing over drums and sheaves or
in areas where problems existed in previous ropes.
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A wire break may appear as nothing more than a crack in the wire,
and again can be easily overlooked. If the inspector notes a “flaw” in a wire,
it should be carefully checked. The inspector should carry some type of magnifying device
To determine if a flaw is actually a break. If a break has occurred,
thoroughly check the area for additional breaks, both on the crown and in the valleys.
Remember, valley breaks in round strand ropes are
difficult to determine; Compaction only increases the difficulty.
The inspector must be slow and methodical in inspecting compacted ropes;
a quick check will reveal nothing.
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A wire break may appear as nothing more than a crack in the wire, and again can be easily overlooked.
If the inspector notes a “flaw” in a wire, it should be carefully checked.
The inspector should carry some type of magnifying device to determine if a flaw is actually a break.
If a break has occurred, thoroughly check the area for additional breaks,
both on the crown and in the valleys.
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Remember, valley breaks in round strand ropes are difficult to
determine; compaction only increases the difficulty.
The inspector must be slow and methodical in inspecting compacted ropes;
a quick check will reveal nothing.
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Overall, perhaps the most important inspection technique
is recognizing the limits of wire rope. While it’s true that compacted and
plastic infused ropes are more durable, neglect and
abuse will still quickly end the rope’s life.
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There is no substitute for proper installation,
handling and
inspection techniques in combination
with a preventative maintenance program.
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Troubleshooting Checklist
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Tension Break Wire break shows one end of broken wire coned,
the other cupped. Necking down of the broken ends is typical of this type break.
Where tension breaks are found, the rope has been subjected to overloading, either for its original strength (new rope) or
for its remaining strength in the case of a used rope. Tension breaks frequently are caused
by the sudden application of a load to a slack rope, thereby setting up incalcuable impact stress.
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Abrasion Break Wire break shows broken ends worn to a knife-edge thinness. Abrasive wear obviously is concentrated at
points, where the rope contacts an abrasive medium, Such as the grooves of sheaves and drums,
or other objects with which the rope comes into contact. Unwarranted abrasive wear indicates
improperly grooved sheaves and drums, incorrect fleet angle,
or other localized abrasive conditions.
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Fatigue Break Wire breaks are usually transverse or square showing granular structure.
Often these breaks will develop a shattered or jagged fracture,
depending on the type of operation. Where fatigue breaks occur,
the rope has repeatedly been bent around too small a radius.
Whipping, vibration,
slapping and tensional stresses will also cause fatigue.
Fatigue breaks are accelerated by abrasion and nicking.
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Corrosion Break Easily noted by the wire’s pitted surface,
wire breaks usually show evidence of tension, abrasion
and/or fatigue. Corrosion usually indicates improper lubrication.
The extent of the damage to the interior of the rope is extremely difficult to determine;
consequently corrosion is one of the most dangerous
causes of rope deterioration.
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Cut or Shear Wire will be pinched down and cut at broken ends, or
will show evidence of shear-like cut. This condition is evidence of mechanical abuse
caused by agents outside the installation, or by something abnormal on the installation itself,
such as a broken flange. Tension & Wear
Abrasion Fatigue
Wear Fatigue Nicking
Corrosion Cut or Shear
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ABRASION Frozen sheaves or rollers Tight grooves
Excessive fleet angle Oversized or undersized rope Corrugated sheave or drum
Sheave overspin Rope jumping the sheave
Poor spooling Misaligned sheaves Site contaminants
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CORE PROTRUSION AND SLIPPAGE
Shockloading Poor seizing techniques
Poor installation techniques Lack of lubrication
Environmental damage, e.g. acidic Fume exposure
Improper storage
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CORROSION Poor installation techniques Crosswinding
Poor Spooling Incorrect wire rope construction
Poor break-in procedure Excessive fleet angle Excessive rope length
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CRUSHING Lack of lubrication (fiber core)
Excessive abrasion Corrosion,
internal and/or external Inner wire or core failure
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DIAMETER REDUCTION
Out of round sheaves Tight grooves
Misaligned sheaves Undersized sheaves
Worn bearings Vibration Slapping Whipping
Reverse bends
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FATIGUE Poor seizing techniques
Tight grooves Undersized sheaves
Poor installation techniques
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HIGH STRANDING Poor spooling
Excessive rope length Broken flange
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JUMPING THE SHEAVE
Poor unreeling procedures Poor installation techniques
Undersized sheaves
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KINKING Poor installation techniques Poor unreeling procedures
Corrosion Core Failure
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LAY LENGTHENING & TIGHTENING
Poor installation techniques Undersized sheaves Oversized sheaves
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LOOPED WIRES UNBALANCED
ROPE Abrasion
Core Protrusion (Shockloading) Corrosion Crushing
Fatigue (Reverse Bend) Fatigue (Undersized Sheave)
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Wire Rope Inspection The most widely used wire rope
replacement, inspection and maintenance standard for mobile-
type cranes is ASME B30.5, section 5-2.4. The following is an
excerpt from that standard.
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162
When an inspection discloses any unsatisfactory
conditions in a line, ensure the line is destroyed or cut
into small pieces as soon as possible. This precaution
prevents the defective line from being used.
N.A.A.R.S.O. 2/12/2015