General Information on wire rope

The three basic components of a typical wire rope. (Fiber core is shown)

• COMPONENTS: Wire rope consists of three basic components.

1. Wires.

2. Strands, formed by wires, laid helically around a core.

3. Core, or center.

• MATERIAL: Steel grades in wide use today are IPS (improved plow steel), EIPS (extra improved plow steel), sometimes

also referred to as XIPS, XIP, or EIP, as well as EEIPS (extra, extra improved plow steel).

• CORE: Its function is to provide proper support for the strands under normal conditions. Three types of core (or center)

are commonly used.

1. Fiber Core (F.C.), usually polypropylene (P.sometimes hemp (H.C.) and sisal.

2. Independent Wire Rope (IWRC)

3. Wire Strand (WSC)

IWRCand WSCare sometimes referred to as steel wire core or steel center.

• CONSTRUCTION: Expressed in numbers of strands x number of wires. 6 x 25 indicates that the wire rope consists of

6 strands, which in turn have 25 individual wires. Constructions are grouped into classes:

6 x 7 Class: Containing 6 strands that are made up of 3 through 14 wires, of which no more than 9 are outside wires.

6 x 19 6 strands that are made up of 15 through 26 wires, of which no more than 12 are outside wires.

6 x 36 6 strands that are made up of 27 through 49 wires, of which no more than 18 are outside wires.

8 x 19 8 strands that are made up of 15 through 26 wires, of which no more than 12 are outside wires.

19 x 7 19 strands, each of which is made up of 7 wires.

8 x 19 and 19 x 7 class wire ropes have rotation-resistant properties, excluding elevator ropes.

The constructions listed above are just some of the more popular constructions.

Other common constructions:

7 x 7, 7 x 19: Galvanized cable. Sometimes referred to as “aircraft cable” but not intended for aircraft use.

1 x 7, 1 x 19: Strand

7 x 7 x 7, 7 x 7 x 19: Cable Laid

Many others exist, some for highly specialized applications only.

Note that any class denotes the nominal number of wires in each strand. The actual number of wires may be different. For example 6 x 36 class: strands most commonly consist of 36 wires, or 31, or 41.

• STRANDPATTERNS: They refer to different types of arrangements of wires and their diameters within a strand.

Common strand patterns are Filler Wire, Seale, Warrington and combinations thereof.

LAY: indicates how the wires have been laid to form strands and how the strands have been laid around the core. A

right regular lay rope (RRL; the most common) has its strands laid right on the rope - similar to threading a right-hand threaded bolt. Regular means that the direction of the wire lay in the strand is opposite to the direction of the strand lay in the rope. (The wires in regular lay rope appear to be in line with the axis of the rope).

CAUTION: When combining separate ropes in a single line application always use ropes of the same lay pattern. Different lays can increase rotation at connection points decreasing rope efficiency.

• PREFORMING: Amanufacturing process wherein the strands and their wires are permanently formed - during

fabrication - to the helical shape that they will ultimately assume in the finished wire rope. Proper preforming prevents the strands and wires from unlaying during normal use. The vast majority of wire rope sold today is preformed.

• FINISH: Wire rope is either sold as “bright” (or “black”) - meaning uncoated, or galvanized for better corrosion

resistance. “Drawn Galvanized” wire has the same strength as bright wire, but wire, “galvanized at finished size” is usually 10% lower in strength. Plastic coated wire rope is also available, usually galvanized or stainless steel cable. The most common plastic coatings are vinyl or nylon in either clear or white, although other materials and colors are available. These coatings do not add strength to the wire rope itself.

• LUBRICATION: During fabrication, wire ropes receive lubrication. The kind and amount depends on the rope’s size,

type and use, if known. This in-process treatment will provide the finished wire rope with ample protection for a reasonable time if it is stored under proper conditions. But, when the wire rope is put into service, the initial lubrication will normally be less than needed for the full useful life of the wire rope. Because of this, periodic applications of a suitable wire rope lubricant are necessary.

• ORDERINGWIRE ROPE: Construction, lay, core, finish and other factors mentioned above impart greatly differing

characteristics to different wire ropes. They must be understood and considered when selecting wire rope. There is

no perfect wire rope for all applications; usually some less desirable properties are traded off for other, more desirable ones. Refer to the Wire Rope Users Manual by the Wire Technical Board for a better understanding of wire rope properties and consult professional help when in doubt.

Lacking a complete description of the wire rope desired, a supplier can make several assumptions:

1. If direction and type of lay are omitted from the rope description, it is assumed to be right regular lay (RRL).

2. If finish is omitted, this will be presumed to mean ungalvanized, “bright” finish.

3. no mention is made with reference to preforming, preformed wire rope will be supplied.

4. a supplier receives an order for 6 x 19 wire rope he may assume this to be a class reference and is, therefore, legally justified in furnishing any construction within this category.

Proper handling of wire rope

• Measuring of wirerope

How to measure (or caliper) a wire rope correctly. Since the “true” diameter (A) lies within the circumscribed

circle, always measure the larger dimension (B). Actual diameter can be 5% larger than nominal wire rope diameter.

• RECEIVING AND STORING WIRE ROPE

Make certain that the wire rope received is the one that was ordered. Check for obvious damage to wire rope

and reel. Store wire rope away from heat, moisture and other corrosive agents. This means storing under a

weatherproof cover, off the ground, preferably in a dry, cool, well ventilated warehouse. If wire rope has to be

kept outdoors, cover it with a coating of protective wire rope lubricant and cover both wire rope and reel with

waterproof material. Keep it well off the ground. Careful inspection after extended storage is of utmost importance.

• UNREELING OR UNCOILING WIRE ROPE

Great care must be taken when removing wire rope from reels or coils. Looping the rope over the flange of the

reel or pulling the rope off a coil while it is lying on the ground will create loops in the line. If these loops are

pulled tight, kinks will result, thereby permanently damaging the wire rope. Check illustrations below showing

correct and incorrect ways of unreeling and uncoiling wire rope.

Whenever handling wire rope, take care not to drop reels or coils. This can damage wire rope and collapse the

reel, making removal of the wire rope extremely difficult if not impossible.

When reeling wire rope from one reel to another it is preferable for the wire rope to travel from top to top, as illustrated. Spooling from bottom to bottom is also acceptable, provided the surface over which the wire rope will travel is clean, smooth and dry, so as not to allow foreign particles to become embedded in the wire rope. Spooling from top to bottom or from bottom to top can put a reverse bend into wire rope and must be avoided. When stringing up on machinery wire rope should be removed from the reel in the same direction as placed on the drum.

There are numerous ways to cut wire rope - use only appropriate tools specifically designed to cut wire rope. Safety goggles and work gloves must always be worn. Observe other precautions peculiar to the tools used. Wire rope should be properly seized on both sides of the cut with wire or strand. Seizing wire diameter and the number and length of the seizings will depend on the diameter of the wire rope, and whether or not it is preformed.

• BREAKINGIN NEW WIRE ROPE

Since wire rope is a machine with many moving parts, it requires careful installation and breaking in procedures for maximum safety and long service life. After proper installation, allow the wire rope to run through a cycle of operation at a very low speed. Keep a close watch on the wire rope, its attachments and any working parts such as sheaves, drums, rollers, etc. to make certain that the wire rope runs freely. If no problems appear at this stage, run the wire rope through several cycles of operation under light load at reduced speed. This procedure allows the component parts of the new rope to make a gradual adjustment to the actual operating conditions.

• WIRE ROPE EFFICIENCY

Wire rope will develop 100% efficiency, that is, break at or above minimum acceptance strength (not less than 2 1/2% below nominal breaking strength) under controlled laboratory conditions. Once fittings such as sleeves, clips, sockets, etc. are attached and/or the wire rope passes over a curved surface such as sheaves, pins, etc. its strength is decreased. In the case of wire rope passing over a curved surface this decrease in strength depends on the severity of the bend. In the case of wire rope fittings, the decrease in wire rope strength will depend on the type of fittings used. The wire rope efficiency usually ranges from 70% - 100%. Note, that hand spliced wire rope, while not using any fittings, has less efficiency than properly flemished and swaged wire rope. There are other factors, depending on the application of wire rope, that can cause a decrease in nominal wire rope strength. They must be considered when choosing a design factor. Refer to the Wire Rope Users Manual and/or other qualified sources for details.

• ELASTIC PROPERTIES OF WIRE ROPE

Wire rope is an elastic member; it stretches or elongates under load. This elongation can be permanent or recoverable. The extent of elongation will depend on the wire rope used and the design factor chosen. While it may be acceptable for many wire rope uses to neglect its elastic properties, they are of critical importance for some uses. When in doubt about the importance of wire rope elongation consult professional help. Pre-stretching wire rope will only remove some of the constructional stretch and will not totally eliminate elongation under load.

• WINDING WIRE ROPE ON DRUMS

Installation of wire rope on a plain or grooved drum requires a great deal of care. Make certain the wire rope is properly attached to the drum. Keep adequate tension on the wire rope as it is wound onto the drum. Guide each wrap as close to the preceding wrap as possible, or follow the groove in case of a grooved drum. No blanket recommendations can be given concerning direction of winding, desirable drum diameter, fleet angle, etc. Consult the Wire Rope Users Manual for this and other important technical information.

• WIRE ROPE SLINGS

Refer to ASMEstandard B30.9 and OSHAstandard 1910.184 for design factors and other important information. Other standards and information may apply.

SPECIALTYWIREROPES- Florida Wire & Rigging Works also carries many ropes designed for specific applications such as the following:

ELEVATOR WIRE - Elevator wire is availabel in traction steel and extra high strength, in 6 X 19 or 8 X 19 construction. wire rope is constructed to withstand the continuous bending and abrasive conditions of elevators, with extra high strength for modern, high speed elevators. The type of wire is designated be the elevator manufacturer.

ALTERNATELAY- In alternate lay wire rope there are alternating land and regular lay strands. The use is somewhat limited - the advantages are distortion resistance and preventing clamp slippage. Another available variation is made with two lang strands alternating with one regular strand.

AIRCRAFTCABLE- Small cables ranging from 1/64” to 3/8” (not all constructions ar available in every size) for a variety of uses - boat rigging, control cables, guys, etc., are available in 1 X 7, 1 X 19, 7 X 19, and 7 X & constructions. Aifrcraft cable can be supplied in galvanized finish or stainless steel. All aircraft cable supplied by Florida Wire & Rigging Works meets or exceeds current federal and MIL specifications. Aircraft cable is also available with plasic and vinyl coatings for certain applications.

SLING ANGLES AFFECT THE LOAD ON LEGS OF A SLING

Sling angle or angle of loading is the angle measure between a horizontal line and the sling leg or body. This angle is very important and can have a dramatic effect on the rated load of the sling. As illustrated here, when this angle decreases, the load on each leg increases. This principle applies whether one sling is used with legs at an angle in a basket hitch, or for multi-leg bridle slings. Horizontal sling angles of less than 30 degrees shall not be used.

1) Rated load (rated capacity) of a wire rope sling is based upon the nominal, or catalog, strength of the wire rope used in the sling. And factors which affect the overall strength of the sling. These factors include attachment or splicing efficiency, the number of parts of rope in the sling, type of hitch (e.G. Straight pull, choker hitch, basket hitch), diameter around which the body of the sling is bent, and the diameter of pin (or hook) over which the eye of the sling is rigged.

2) load of a sling is different for each of the three basic methods of rigging (see graphic above.) These rated loads are available from us and are indicated on the tag attached to the sling at the time it is fabricated (if requested by the user).

3) Warning: a hand-tucked eye splice can unlay (unravel) and fail if the sling is allowed to rotate during use.

4) Never “shock load “ a sling. There is no practical way to estimate the actual force applied by shock loading. The rated load of a wire rope sling can easily be exceed by a sudden application of a force, and damage can occur to the sling. The sudden release of a load can also damage a sling.

5) The body of a wire rope sling should be protected with corner protectors, blocking or padding against damage by sharp edges or corners of a load being lifted. Sharp bends that distort the sling body damage the wire rope and reduce its strength.

6) Any angle other than vertical at which a sling is rigged increases the loading on the sling.

7) sling should be given a visual inspection before each lift or usage to determine if it is capable of safely making the intended lift. An inspection should include looking for such things as:

• Broken wires.

• Kinks or distortions of the the sling body.

• Condition of eyes and splices, and any attached hardware.

• Reduction in diameter of the rope.

• Corrosion.

8) Whenever a sling is found to be deficient, the eyes must be cut, or other end attachments or fittings removed to prevent further use, and the sling body discarded.

9) sling eye should never be used over a hook or pin with a body diameter larger than the natural width of the eye.

Never force an eye onto a hook. The eye should always be used on a hook or pin with at least the diameter of the rope.

VERTICAL, or straight, attachment is simply using a sling to connect a lifting hook or other device to a load. Full rated load of the sling may be used, but never exceeded. Atagline should be used on such a lift to prevent rotation which can damage the sling. sling with a hand tucked splice can unlay and fail if the sling is allowed to rotate.

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 sling body at the choke point.

Warning!!

Failure to follow warnings & instructions may result in serious injury or death

Refer to warnings on pages 4-6.

These warnings also apply to Wire Rope & Cable. Only additional warnings and information are listed below.

• WIRE ROPE IS A MACHINE. Understand and respect it.

Like any machine, it needs proper care and maintenance for optimal safety and long service life. For a better understanding of wire rope we highly recommend the Wire Users Manual by the Wire Technical Board. Wire Technical Board 801 North Fairfax Street, Suite 211, Alexandria VA22314-1757. Phone: (703) 299-8550 Fax:(703) 299-9253.

• Rated Capacity.

Rated capacity is the load which a new wire rope may handle under given operating conditions and at assumed design factor. Adesign factor of 5 is chosen most frequently for wire rope. (Operating loads not to exceed 20% of catalog Breaking Strength.) loads may have to be reduced when life, limb or valuable property are at risk or other than new rope is used. design factor of 10 is usually chosen when wire rope is used to carry personnel. (loads not to exceed 10% of catalog Strength.)

Responsibility for choosing a design factor rests with the user.

• Attachments must have at least the same Working Load Limit as the wire rope used.

Clips, sockets, thimbles, sleeves, hooks, links, shackles, sheaves, blocks, etc. must match in size, material and strength to provide adequate safety protection. Proper installation is crucial for maximum efficiency and safety.

• Keepout from under araised load.

Do not operate load over people. Do not ride on load. Conduct all lifting operations in such a manner that if equipment were to fail or break, no personnel would be injured . This means: KEEP OUTFROM UNDER A RAISED LOAD, DO NOTOPERATE LOADS OVER PEOPLE AND OUT OF THE LINE OFFORCE OF ANY LOAD.

• Avoid shock loads.

Avoid impacting, jerking or swinging of load. Working Load limit will not apply in these circumstances because a shock load is generally significantly greater than the static load.

• Inspect regularly.

Use inspection instructions as guidelines only. Additional technical information on wire rope inspection can be obtained from the sources listed under ADDITIONAL REFERENCE MATERIALon page 6. Two of the most important prerequisites for inspecting wire rope are technical knowledge and experience.

heck the general condition of the wire rope. Also, look for localized damage and wear, especially at wire rope attachments. Inspect all parts that come in contact with the wire rope. Poor performance of wire rope can often be traced back to worn or wrong-sized sheaves, drums, rollers, etc. Look for kinks, broken wires, abrasions, lack of lubrication, rust damage, crushing, reduction of diameter, stretch or other obvious damage. If any of these conditions exists or if there is any other apparent damage to the wire rope, retire the wire rope according to the instructions below.

When in doubt about the extent of the damage, retire the wire rope in question immediately. Without laboratory analysis, it is impossible to determine the strength of damaged or used wire. Thus, you will not be able to tell whether wire rope with any amount of damage is safe to use. Retire the wire rope that is damaged. For specific inspection procedures check various OSHA and ANSI publications.

• Destroy, ratherthandiscard, toberetired.

Wire rope that is not destroyed might be used again by someone not aware of the hazard associated with that use. Destroying wire rope is best done by cutting it up into short pieces.