steel wire ropes and slings.pdf

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Wire Ropes

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Characteristics like fatigue resistance and resistance to abrasion are directly affected by the design of strands. In most strands

with two or more layers of wires, inner layers support outer layers in such a manner that all wires may slide and adjust freely whenthe rope bends. As a general rule, a rope that has strands made

up of a few large wires will be more abrasion resistant and lessfatigue resistant than a rope of the same size made up of strands with many smaller wires.

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Single Layer. The most common example of the single layer

construction is a 7-wire strand. It has a single-wire center with six

wires of the same diameter around it.

Seale. This construction has two layers of wires around a

center wire with the same number of wires in each layer. All

wires in each layer are the same diameter. The strand is

designed so that the large outer wires rest in the valleys

between the small inner wires.

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Filler Wire. This construction has two layers of uniform-size wire

around a center wire with the inner layer having half the number of wires as the outer layer. Small filler wires, equal in number to the

inner layer, are laid in the valleys of the inner layer.

Warrington. This construction has two layers with one diameter

of wire in the inner layer, and two diameters of wire alternating large and small in the outer layer. The larger outer-layer wires

rest in the valleys, and the smaller ones on the crowns, of the

inner layer.

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Combined patterns. When a strand is formed in a single

operation using two or more of the above constructions, it is referred to as a "combined pattern."

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Standard Rope ClassificationsAll rope of the same size, grade, and core in each classification have the same minimum breaking force and weight per meter. Different constructions within each classification differ in working characteristics. These characteristics must be

considered whenever you're selecting a rope for a specific application.

50 through 746x61

27 through 496x36

16 through 266x19

7 through 156x7

Wires per strandClassification

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Special Rope ConstructionsUnusual operating conditions often require ropes of special design to

better withstand stresses or environments that would seriously impair

performance of more conventional designs. Ropes that may meet these

needs include the following:

Flex-X®. A special process that creates more strand surface

area on each strand to help spread contact, decrease wear, reduce corrugation and extend service life. With greater surface

area and more steel per diameter than conventional ropes, Flex-X provides higher strength and better wear resistance. Its high-

density strands are compacted for extra strength and resistance

to abrasion, crushing, and bending fatigue.

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TUF-KOTE®/PFV®. A plastic impregnated wire rope proven to

provide longer service life and a cleaner operation. On the

inside, top-of-the-line wire rope effectively withstands the

demanding pressures of your job. The polymer is applied at

high pressure to force the material into the rope, serving to

cushion the strands, distribute internal stresses, keep in wire rope lubricant and keep out dirt and debris. On the outside, the

engineered polymer plastic is designed to provide a cleaner operation and reduces wear on sheaves and drums.

TUF-MAX These shovel ropes are manufactured with an

enhanced coating process that makes them more resistant to

external rope wear and helps extend drum and sheave life.

Special Rope Constructions

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7-Flex®. A rope construction that offers improved resistance

to bending fatigue compared to a 6 strand rope of the same

diameter due to a combination of the outer wire size and the

seventh strand. The use of a 26 Warrington Seale (WS) strand

construction provides a good balance of operating

characteristics.

8 strand wire ropes. In general, 8 strand wire ropes are

designed for specialized applications that can take advantage of their special traits. An 8 strand rope will have smaller

strands and a larger core than a 6 strand rope of the same diameter. So, it can be expected to display greater

bendability, but lower minimum breaking force due to the reduction in metallic area of strand cross-sections. A

standard 8 strand rope will be less stable, as a general rule,

than a 6 strand rope and will be more subject to crushing,

especially when it has a fiber core.


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Flattened (triangular) strand. These ropes feature

"shaped" strands formed so they will close together to

achieve greater metallic area in the rope's cross-section

and greater bearing surface for contact with sheaves and

drums.

Swaged ropes. These ropes offer higher strength than

standard ropes of the same diameter while providing

greater resistance to drum crushing, scrubbing, and

similar surface wear. During manufacture, the rope is

swaged to produce a compact cross-section with

minimum voids and greater surface area.


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Basic Types of Wire Ropes

� Bright Wire. Most ropes are made with an uncoated (bright) wire that is manufactured from high-carbon steel. The

chemistry of the steel used and the practice involved in drawing the wire are varied to supply the ultimate combination of tensile strength, fatigue resistance, and wear resistance in the finished rope.

� Stainless steel wire. This is a special alloy containing approximately 18% chromium and 8% nickel. It has high resistance to many corrosive conditions.

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� Galvanized Wire: These are often used to improve corrosion

resistance of wire ropes and are used in wet or corrosive conditions.

�Galvanized to finished size wire. This is first drawn as a bright wire to

a predetermined size that's smaller than the required finished wire size. This

wire is then run through the galvanizing line, and the resultant coating of

zinc increases the wire diameter to the finished size. Galvanized to finished

size wire has a strength 10% lower than the same size and type of bright

wire. Ropes made from this wire therefore have a minimum breaking force

that's 10% lower than the equivalent size and grade of bright rope.

�Drawn galvanized wire: This is galvanized before the final drawing to

finished size. Since the galvanized coating also goes through the drawing

process, it is much thinner than the coating on galvanized to finished size

wire. Drawn galvanized wires are equal in strength to the same size and

type of bright wire and drawn galvanized rope is equal in strength to the

same size and grade of bright rope.

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"Lay" and Rope Design

"Lay" has three meanings in rope design. The first two meanings

are descriptive of the wire and strand positions in the rope. The third meaning is a length measurement used in manufacturing and inspection.

� Left-hand or Right-hand Lay

� Ordinary (Regular) or Lang Lang

� Length Measurement


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� The direction strands lay in the rope -- right or left. In a standard

rope the strands twist around the core like a screw thread. If the

strands twists in the same direction as the right-hand thread then the

rope is in right-hand lay. If the strands twist in the opposite direction

it is in left-hand lay.

� The relationship between the direction strands lay in the rope and

the direction wires lay in the strands. If the wires twists in the same

direction as the strands, then the the rope is in Lang’s lay. If the

wires twist in the opposite direction to that of the strands, then the

rope in ordinary (regular) lay.


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Identification of Lang’s Lay or Ordinary lay


The lay of a rope affects its operational characteristics.

� Lang lay is more fatigue resistant and abrasion resistant.

� While Regular (Ordinary) lay is more stable and more resistant to

crushing than lang lay.

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Lang right-hand

Ordinary right-hand

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Ordinary Left Hand

Lang Left Hand

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� The length of lay (pitch) of a standard rope is the distance, measured along

the rope, between the crown (highest point) of a strand and the next crown of

that strand along the rope.

� This is a measurement frequently used in wire rope inspection. Standards

and regulations require removal when a certain number of broken wires per rope lay are found.

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Wire Rope Grades

� Ropes are available in 3 grades, Improved Plow Steel (IPS), Extra

Improved Plow Steel (XIP) and Extra Extra Improved Plow Steel (XXIP).

� The most common grade of rope today is called Extra Improved Plow

Steel Grade (XlP®). For most ropes, this will be the grade supplied. XIP

IWRC ropes have a 15% higher minimum breaking force than Improved

Plow Steel Grade (IPS), the former standard strength.

� Other grades of wire rope are also available, including Extra Extra

Improved Plow Steel Grade (XXIP®). Many equipment designers are

specifying XXIP grade wire rope for the operating ropes on modern

higher-rated equipment. They're taking advantage of its higher

minimum breaking force to help reduce total system weight. New

machines can be designed with higher ratings using smaller diameter

rope due to XXIP's higher strength. Minimum breaking force of XXIP

grade wire rope is 10% higher than XIP grade.

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Preforming

� Preforming preshapes strands before the rope is completed. This process helically shapes the wires and strands into the shape they will assume in the finished rope. It improves handling and resistance to kinking by conforming the strands to the position they take in the rope.

� The preforming minimizes internal stresses within the rope. Today, preforming is virtually standard in rope manufacture, and non-preformed rope is made only on special order.

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Choosing the Right Wire Rope

All wire ropes feature design characteristics. In most cases, a wire rope cannot increase both fatigue resistance and abrasion resistance. For example, when we increase fatigue resistance by selecting a rope with more wires, the rope will have less abrasion resistance because of its greater number of smaller outer wires.

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Choosing the Right Wire Rope

When you need wire rope with greater abrasion resistance, one choice is a rope with fewer (and larger) outer wires to reduce the effects of surface wear. But that means the rope's fatigue resistance will decrease. That's why you need to choose your wire rope like you would any other machine, very carefully. You must consider all operating conditions and rope characteristics.

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The basic characteristics of wire rope� How do you choose the wire rope that’s best suited for your

job? The following are the most common characteristics to be considered when selecting a rope for your application.

�Strength.

�Fatigue Resistance.

�Crushing Resistance.

�Resistance to metal loss and deformation.

�Resistance to rotation.

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Strength. Wire rope strength is usually measured in tonnes. In published material, wire rope strength is shown as "nominal" strength, catalog strength or minimum breaking force. They all refer to the calculated strength figures that have been acceptedby the wire rope industry.

�When placed under tension on a test device, a new rope should

break at a figure equal to or higher than the minimum breaking force

shown for that rope.

�The minimum breaking force applies to new, unused rope. A rope

should never operate at or near the minimum breaking force. During

its useful life, a rope loses strength gradually due to natural causes

such as surface wear and metal fatigue.

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Fatigue resistance. Fatigue resistance involves metal fatigue of the wires

that make up a rope. To have high fatigue resistance, wires must be capable

of bending repeatedly under stress - for example, a rope passing over a

sheave.

�Increased fatigue resistance is achieved in a rope design by using a large

number of wires. In general, a rope made of many wires will have greater

fatigue resistance than a same-size rope made of fewer, larger wires

because smaller wires have greater ability to bend as the rope passes

over sheaves or around drums. To overcome the effects of fatigue, ropes

must never bend over sheaves or drums with a diameter so small as to

bend wires excessively. There are precise recommendations for sheave

and drum sizes to properly accommodate all sizes and types of ropes.

�Every rope is subject to metal fatigue from bending stress while in

operation, and therefore the rope's strength gradually diminishes as the

rope is used.

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Crushing resistance. Crushing is the effect of external pressure

on a rope, which damages it by distorting the cross-section shape of the rope, its strands or core - or all three.

� Crushing resistance therefore is a rope's ability to withstand or resist

external forces, and is a term generally used to express comparison

between ropes.

� When a rope is damaged by crushing, the wires, strands and core

are prevented from moving and adjusting normally during operation.

� In general, IWRC ropes are more crush resistant than fiber core

ropes. Regular lay ropes are more crush resistant than lang lay

ropes. 6 strand ropes have greater crush resistance than 8 strand

ropes or 19 strand ropes.

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Resistance to metal loss and deformation. Metal loss refers to the actual wearing away of metal from the outer wires of a rope, and metal deformation is the changing of the shape of outer wires of a rope.

� In general, resistance to metal loss by abrasion (abrasion resistance) refers

to a rope's ability to withstand metal being worn away along its exterior. This

reduces strength of a rope.

�The most common form of metal deformation is generally called "peening" -

since outside wires of a peened rope appear to have been "hammered"

along their exposed surface. Peening usually occurs on drums, caused by

rope-to-rope contact during spooling of the rope on the drum. It may also

occur on sheaves.

�Peening causes metal fatigue, which in turn may cause wire failure. The

hammering - which causes the metal of the wire to flow into a new shape -

realigns the grain structure of the metal, thereby affecting its fatigue

resistance. The out-of-round shape also impairs wire movement when the

rope bends.

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Inspection

� All wire ropes will wear out eventually and gradually lose work capability throughout their service life. That's why periodic inspections are critical.

� Regular inspection of wire rope and equipment should be performed for three good reasons:

� It reveals the rope's condition and indicates the need for

replacement.

� It can indicate if you're using the most suitable type of rope.

� It makes possible the discovery and correction of faults in equipment

or operation that can cause costly accelerated rope wear.

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Inspection

� All wire ropes should be thoroughly inspected at regular intervals. The longer it has been in service or the more severe the service, the more thoroughly and frequently it should be inspected. Be sure to maintain records of each inspection.

� Inspections should be carried out by a person who has learned through special training or practical experience what to look for and who knows how to judge the importance of any abnormal conditions they may discover. It is the inspector's responsibility to obtain and follow the proper inspection criteria.

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What to Look for

Here's what happens when a wire breaks

under tensile load exceeding its strength. It's

typically recognized by the "cup and cone"

appearance at the point of failure. The

necking down of the wire at the point of failure

to form the cup and cone indicates failure has

occurred while the wire retained its ductility.

This is a wire with a distinct fatigue break.

It's recognized by the square end

perpendicular to the wire. This break was

produced by a torsion machine that's used

to measure the ductility. This break is

similar to wire failures in the field caused by

fatigue.

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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.

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.

What to Look For

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Here you see a single strand removed from a

wire rope subjected to "strand nicking." This

condition is a result of adjacent strands

rubbing against one another. While this is

normal in a rope's operation, the nicking can

be accentuated by high loads, small sheaves

or loss of core support. The ultimate result

will be individual wire breaks in the valleys of

the strands.

What to Look For

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Typical evidence of Wear and Abuse

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.

A typical failure of a rotary drill line with a poor cutoff practice. These wires have been subjected to continued peening, causing fatigue type failures. A predetermined, regularly scheduled cutoff practice can help eliminate this type of problem.

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This is localized wear over an equalized sheave. The danger here is that it's invisible during the rope's operation, and that's why you need to inspect this portion of an operating rope regularly. The rope should be pulled off the sheave during inspection and bent to check for broken wires.

This is a wire rope with a high strand -- a condition in which one or more strands are worn before adjoining strands. This is caused by improper socketing or seizing, kinks or dog-legs. It recurs every sixth strand in a 6 strand rope.

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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.

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 shear breaks that appear to have been cut on an angle.

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Drum crushing is caused by small drums, high loads and multiple winding conditions.

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When to Discard a Rope: To decide when a rope should

be discarded it is necessary to take into account the state of the rope and the conditions under which it works. As a general rule ropes should be discarded when any one of following occurs:

� The factor of safety has become too low (when the reserve of strength is

no longer sufficient to ensure that the rope can safely withstand the

repeated shock loads, bends, etc.)

� The loss in rope strength due to wear, corrosion, or both is approaching

one-sixth (or 16%) of the original strength.

� The outer wires have lost about one-third (or 33%) of their depth as a

result of any form of deterioration.

� The rope has become kinked or otherwise deformed, distorted, or

damaged, and the affected part cannot be cut out.

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When to Discard a Rope

� The rope has been subjected to a severe overwind or overload, or to

severe shock loading, as a result of an accident.

� An examination or NDT of the rope leaves any doubt as to its safety on

any grounds.

� A rope, which is still in good condition, reaches its maximum statutory

life or the maximum life specified by a competent person.

� The loss in rope strength due to fatigue, corrosion-fatigue, surface

embrittlement, cracked or broken wires of any kind, is approaching one-

tenth (or 10%) of the original strength. The loss in strength may be

estimated by regarding all broken or cracked wires within a length of two

rope lays as no longer contributing any strength to that part of the rope.

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Removal Criteria� A major portion of any wire rope inspection is the detection of broken

wires. The number and type of broken wires are an indication of the

rope's general condition and a benchmark for its replacement.

� Frequent inspections and written records help determine the rate at

which wires are breaking. Replace the rope when the values given in the

table are reached.

� Valley wire breaks -- where the wire fractures between strands or a

broken wire protrudes between strands -- are treated differently than

those that occur on the outer surface of the rope. When there is more

than one valley break, replace the rope.

� Broken wire removal criteria cited in many standards and specifications,

apply to wire ropes operating on steel sheaves and drums. For wire

ropes operating on sheaves and drums made with material other than

steel, please contact the sheave, drum or equipment manufacturer or a

qualified person for proper broken wire removal criteria.

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Not SpecifiedNot Specified6**ANSI/A10.5

22**236**Personnel hoistsANSI/A10.4

Not SpecifiedN/S412**Overhead hoistsASME/B30.16

23236**Floating cranes & derricks

ASME/B30.8

23236**Base-mount drum hoistsASME/B30.7

23236**DerricksASME/B30.6

2 randomly distributed broken wires in 6 rope diameter or 4 randomly distributed broken wires in 30 rope diameter.**

Rotation –

resistant ropes

23236**Running ropesMobile cranes

ASME/B30.5

23236**Portal, tower & pillar cranes

ASME/B30.4

Not specifiedNot specified

412**Overhead and gantry cranes

ASME/B30.2

At end connection

In one rope lay

At end connection

In one strand

In one rope lay

EquipmentStandard

NO OF BROKEN WIRES IN STANDING ROPES

NO OFBROKEN WIRES IN RUNNING ROPE

Table - Removal Criteria

** Also remove for one (1) valley break

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Extending Rope Service Life

How long will your rope last?There is not a simple answer but, rather, there are several factors involved, including:

� The manner in which you install and "break in " your new rope.

� The operating technique and work habits of the machine operators.

� Physical maintenance of the rope throughout its service life.

� Physical maintenance of the system in which your rope operates.

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Rope Installation

� Install your rope correctly. The primary concern when installing

a new rope is to not trap any twist in the rope system. Proper handling of the rope from the reel or coil to your equipment will help avoid this situation. Another important step on smooth faced drums is to spool with wraps tight and close together on the first layer. This layer forms the foundation for succeeding layers. Finally, spool the remaining rope on the drum with tension approximating 1% to 2% of the rope's minimum breaking force.

� Break in your new rope properly. When you install a new

operating rope, you should first run it for a brief period of time with no load. Then, for best results, run it under controlled loads and speeds to enable the wires and strands in the rope to adjust to themselves.

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Rope Installation

"Constructional" stretch. When first put into service, new

ropes normally elongate while strands go through a process of seating with one another and with the rope core. This is called "constructional" stretch because it is inherent in the construction of the rope, and the amount of elongation may vary from one rope to another. For standard ropes, this stretch will be about 1/4% to 1% of the rope's length. When constructional stretch

needs to be minimized, ropes may be factory prestretched. Please specify when placing your order.

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Cut off ends to move wear points.� If you observe wear developing in a localized area, it may be beneficial to cut off

short lengths of rope. This may require an original length slightly longer than you

normally use. When severe abrasion or numerous fatigue breaks occur near one

end or at any one concentrated area -- such as drag ropes on draglines or closing

lines in clamshell buckets, for example -- the movement of this worn section can

prolong rope life.

� Wire breaks from vibration fatigue occur at end terminations, so short lengths cut

off there with reattachment of the socket may prolong the rope's life. When broken

wires are found, you should cut off sections of rope. In the case of a socket, you

should cut off at least five or six feet. In the case of clips or clamps, you should cut

off the entire length covered by them.

� Where there is an equalizing sheave, such as that found in many overhead cranes,

fatigue is localized at rope tangency points to the equalizing sheave. Rope life will

be increased if you shift this point by cutting off a short length at the end of one of

the drums. Be sure to make this cutoff before significant wear occurs at the

equalizing sheave, and always do so at the same drum.

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Extending Rope Service

Reversing ends.� Frequently, the most severe deterioration occurs at a point too

far from the end or is too long to allow the worn section to be cut off. In such cases, you may turn the rope end for end to bring aless worn section into the area where conditions are most damaging. This practice is beneficial for incline rope and draglines. The change must be made well before the wear reaches the removal criteria. When changing ends, be careful to avoid kinking or otherwise damaging the rope.

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Lubrication.� Wire ropes are lubricated during manufacture so that the

strands -- as well as the individual wires in the strands -- may move and adjust as the rope moves and bends. But no wire rope can be lubricated sufficiently during manufacture to last its entire life. That's why it's important to lubricate periodicallythroughout the life of the rope.

� The surface of some ropes may become covered with dirt, rock dust or other material during their operation. This can prevent field-applied lubricants from properly penetrating into the rope, so it's a good practice to clean these ropes before you lubricate them.

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Lubrication� The lubricant you apply should be light-bodied enough to

penetrate to the rope's core. You can normally apply lubricant by using one of three methods: drip it on rope, spray it on or brush it on. In all cases, you should apply it at a place where the rope is bending such as around a sheave. Apply lubrication at the top of the bend because that's where the rope's strands are spread by bending and more easily penetrated. In addition, there are pressure lubricators available commercially. Your rope's service life will be directly proportional to the effectiveness of the method you use and the amount of lubricant that reaches the rope's working parts.

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Lubrication

� A proper lubricant must reduce friction, protect against corrosion and

adhere to every wire. It should also be pliable and not crack or separate

when cold yet not drip when warm. Never apply heavy grease to the rope

because it can trap excessive grit, which can damage the rope. Nor

should you apply used "engine oil" because it contains materials that can

damage the rope.

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Warning. In the real world, accidents do happen, and that's why

you need to take special precautions. Before installing wire rope in

your applications, always read and follow the warning label attached to each product.

� Wire rope WILL FAIL, if worn-out, overloaded, misused, damaged, improperly

maintained or abused.

� Wire rope failure may cause serious injury or death!

� Protect yourself and others:

� ALWAYS INSPECT wire rope for WEAR, DAMAGE or ABUSE BEFORE USE.

� NEVER USE wire rope that is WORN-OUT, DAMAGED OR ABUSED.

� INFORM YOURSELF: Read and understand manufacturer's literature.

� REFER TO APPLICABLE CODES, STANDARDS and REGULATIONS for INSPECTION REQUIREMENT and REMOVAL CRITERIA.

� For additional information, ask wire rope supplier.

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Wire Rope Slings

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Wire Rope

Socket

Poured

Spelter or

Resin

Wire

Rope

Socket

Swaged

Mechanical

Splice

oop or

Thimble

Loop or

Thimble

Splice

Hand

Tucked

Wedge

SocketClips

Types of Slings

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How to Use a Sling

Vertical: hitches are made directly from the crane hook to the load. Full rated capacity of the sling may be used but never exceeded. A tagline should be attached to prevent rotation which can damage the sling. A sling with a hand-tucked splice can unlay and fail if the sling is allowed to rotate.

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How to Use a Sling

Choker: hitches reduce lifting capability of a sling, since this method of rigging affects the ability of the wire rope components to adjust during the lift, places angular loading on the body of the sling, and creates a small diameter bend in the body at the choke point.

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How to Use a Sling

Basket: hitches distribute a load equally between the two legs of a sling. Rated capacities are influenced by sling angles.

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Rated Capacity of SlingSling angles have a direct affect on the rated capacity of a sling. This

angle, which is measured between a horizontal line and the sling leg or body, may

apply to a single leg sling in an angled vertical or basket hitch, or to a multi-legged

bridle sling. Anytime pull is exerted at an angle on a leg, the tension or stress on

each leg is increased. To illustrate, each sling leg in a vertical basket hitch absorbs

500 lbs. of stress from a 1,000 lb. load. The same load, when lifted in a 60 degree

basket hitch, exerts 577 lbs. of tension on each leg.

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It is critical therefore, that rated capacities be reduced to account for sling

angles. Angles less than 45 degrees are not recommended and those below

30 degrees should be avoided whenever possible. Use the formula and

chart shown below to calculate the reduction in rated capacities caused by various sling angles.

Actual Sling Capacity = Factor x Rated Capacity

Rated Capacity of Sling

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Rated Capacity of Sling

Rated capacity of a wire rope sling is based upon the nominal or

catalog strength of the wire rope and factors affecting the overall

strength. These factors include termination efficiencies (see chart),

type of hitch, number of rope parts in the sling body, diameter around

which the sling is bent, and diameter of the pin or hook over which the

sling eye is placed.

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Rated Capacity of Sling – Chart

continued

FC2IWRC1

90%

89%

88%

87%

86%

84%

82%

80%

90%

89%

88%

87%

86%

84%

82%

80%

¼”

5/16”

3/8”

7/16”

½”

5/8”

¾”

7/8” thru 2.5”

Loop or Thimbles Splice-Hand Spliced (Tucked)

(Carbon Steel Rope)

92.5%

90%

NE

95%

92.5%

90%

Mechanical Spliced Sheeve (Flemish Eye)

1” diameter and smaller

Greater than 1” diameter thru 2”

Greater than 2” diameter thru 31/2”

NR100%Swaged Socket (Regular Lay Ropes Only)

100%100%Wire Rope Socket (Spelter or Resin)

EfficiencyType of Termination

Termination Efficiencies (Approximate)Applicable to nominal wire rope breaking strengths

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Rated Capacity of Sling – Chart

1. IWRC = Independent Wire Rope Core

2. FC = Fiber Core

3. Typical values when applied properly. Refer to fitting manufacturer for exact values

and method.

NR Not Recommended

NE Not Established

80%80%Clips1

(Depending on Design)

75 to 80%75 to 80%Wedge Sockets3

(Depending on Design)

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• Never force the eye of a sling onto a hook or pin that has a diameter

larger than the natural width of the eye. Also avoid placing a sling eye

onto a hook or pin whose diameter is less than the diameter of the

sling body.

• Rated capacities of fittings and attachments must be equal to or

greater than that of the wire rope sling.

• Never "shock load" a sling. The actual force caused by a sudden

application of load can easily exceed rated capacities and damage a

sling. Abruptly releasing a load can also damage the sling.

• Protect the sling body against sharp edges and corners of loads,

protrusions or abrasive surfaces. Sharp bends can distort wire rope

and reduce its strength.

Precautions while using Slings

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• Fiber core wire rope slings should never be exposed to temperatures

exceeding 200 degrees F. Avoid using IWRC wire rope slings at

temperatures above 400 degrees F or below -60 degrees F.

• Slings are susceptible to damage and strength loss when used in

chemically active environments.

• Slings fabricated with a hand tucked splice can unravel and fail if the

sling is allowed to rotate during use.

• Do not drag slings across floors or pull from underneath loads.

• Avoid twists, kinks and knots before lifting.

• Store wire rope slings where they will not be subjected to dirt,

moisture, extreme heat, corrosion or mechanical damage.

Precautions while using Slings

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steel wire ropes and slings.pdf

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