Wire Rope. Section One. Section One

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Lee Fitzgerald
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DM Standen Ltd has been supplying and distributing wire rope since 1978.

1 DM Standen Ltd has been supplying and distributing wire rope since Apart from the distribution of wire rope, our personnel can supply guidance to users on the correct usage and selection of wire rope. We offer a service ranging from the supply of cut lengths through to wire ropes fi tted with any of our full range of attachments. We are able to source a wide range of alternative rope types to suit your requirements. s and typical minimum break loads are to be used as guides only to assist with the selection of an appropriate rope when taking into account suitable safety factors. 2 DM STANDEN LTD

The steel wire is drawn from rod of diameters between 5 and 10mm to wire of the exact diameter found to give the best performance in the rope to be made.

2 What Is? A wire rope consists of steel wires, in groups of between 6 and 60 or more, twisted together into strands. The strands, numbering between 3 and 8 in simple constructions, are, in turn, twisted together around the core. The steel wire is drawn from rod of diameters between 5 and 10mm to wire of the exact diameter found to give the best performance in the rope to be made. Most specifi cations for wire ropes stipulate outside diameter tolerance of +4% and -1 %, so with upwards of 100 wires per rope the tolerance on each wire is, in effect, very small. As the wire diameter is reduced by drawing through progressively smaller tungsten Carbide Dies, the tensile strength is raised by cold working, so that by varying the number and sizes of dies, a wire can be produced with the correct diameter, with a tensile strength ranging from 140 kgf/mm² to upwards of 220 kgf/mm², and with the required characteristics of hardness and fl exibility. The wires can be galvanised or left uncoated. This account is, of course, simplifi ed. In practice many variables are introduced and the number, size and arrangement of wires in the strand, and of strands in the rope (i.e. the construction of the rope) varies according to the rope specifi cation, to give varying degrees of strength, fl exibility, resistance to abrasion, heat, crushing, shock loading etc. Strand Construction Each strand in a steel wire rope consists of one or more layers of wire laid in a spiral round a centre or king wire (except some marine ropes, in which the centre is of fi bre). The simplest construction consists of one layer of 6 wires of equal diameter round a king wire, while others may consist of up to 4 or more layers of wire. Constructions of steel wire rope are expressed in simple numerical forms showing the number of strands x number of wires per strand and further simplifi ed by being grouped into families known, for example, as the 6 x 19 Group (all of which have 6 strands of between 15 and 25 wires) and 6 x 36 Group (6 strands of between 26 and 41 wires). Core wire Rope wire Strand Steel wire rope Core of natural or synthetic fi bre or steel Equal Lay - all layers of wire are in spirals of the same pitch, so that each wire supports or is supported by its neighbours throughout its length. These constructions are more compact, therefore have a higher density of steel than a cross lay, so the strand is not easily crushed out of shape and the wires do not have points of relatively high contact pressure. Cross Lay - successively layers are not in the same pitch, so that the wires of one layer will cross over wires in the layer below. Although many cross lay constructions have the advantage that all the wires may be of the same diameter, the wires are not as well supported as in equal lay ropes, and damage at the points where wires in two layers cross may reduce rope life. Every time a wire rope bends each wire moves slightly in relation to its neighbours, therefore the sizes and dispositions of the wires are very important to the performance and life of the rope. One distinction can clearly be drawn here between two different types of strand construction - Equal Lay and Cross Lay. DM STANDEN LTD 3

Preforming Preforming is a process by which each strand is shaped to the helical profi le it will adopt in the fi nished rope. If a preformed rope is unlaid (i.e. the strands and wires are separated) it will be seen that the elements all have their set helical forms, and the rope can easily be laid up again.

The process of Preforming is carried out by a Preforming Head, through which the strands pass immediately before the Closing Head, in which they are formed into the wire rope.

3 Preforming Preforming is a process by which each strand is shaped to the helical profi le it will adopt in the fi nished rope. If a preformed rope is unlaid (i.e. the strands and wires are separated) it will be seen that the elements all have their set helical forms, and the rope can easily be laid up again. A Preformed rope had the following advantages: 1) The rope is dead and is therefore more easily handled. 2) When the rope is cut, the cut ends do not automatically unlay (ie. spring open). The process of Preforming is carried out by a Preforming Head, through which the strands pass immediately before the Closing Head, in which they are formed into the wire rope. Lay This Term is applied in various ways: 1) To describe the direction of rotation of wires and strands. 2) The direction of lay or rotation of the strands is normally right hand, but some machinery needs left hand lay ropes. Cores The central core is a steel wire rope maintains the circular cross- section of the rope by supporting the strands around it, and the core may be of two classes: Fibre Cores: composed of vegetable fi bres (e.g.) Manila, Jute or more commonly Sisal) or man made fi bre (such as Polypropylene) which has the advantage of being more resistant to deterioration. Fibre cores are often referred to as FC or FMC (Fibre Main Core), and are impregnated with a suitable preserving lubricant. Steel Cores: may be Wire Strand Core - WSC. - (usually in ropes of a diameter less than 8mm) or a complete rope in itself (an Independent Core - IWRC - usually of 7x7 construction - 6 strands of 7 wires round 1 strand of 7 wires). The steel core will resist distortion when the rope is heavily loaded, passing over relatively small diameter sheaves or pulleys, or subjected to drum crushing. Distortion may lead to impaired running over sheaves etc, and may lead to failure due to unequal loading of individual wires, so where these dangers are present a wire rope with IWRC will normally give a longer fatigue life than one with FC. It is also superior in very hot working conditions, such as steel making plants, where the FC will soon dry out and cease to support the strands. In general, a wire rope with IWRC has a breaking strength 8% higher than a similar rope with FC. Galvanising To protect the rope from corrosion, a coating of Zinc can be applied to the individual wires. Wire Mills apply this zinc coating using the Hot Dip Process, after which the wires are further drawn to the fi nished size. This is known as Drawn Galvanising, and provided an intimate bond between the Zinc and the Steel. The alternative is Finished Galvanising, in which the Zinc is applied after the wire is fully drawn, and although the Zinc coating may be thicker it is more likely to fl ake in service. Lubrication When a wire rope bends, each wire moves in relation to its neighbours, and lubrication helps to reduce friction between wires. It also helps to combat corrosion, external and internal. Specially-selected lubricants have to be applied during the manufacture of the wire rope, the choice of lubricant depending to some extent on the work the rope will be doing. The lubricant helps protect the wires from corrosion during transit and storage, resisting oxidisation and water penetration. During prolonged periods of storage, and during its working life, a wire rope should be examined regularly and further lubricant or dressing may be added if necessary. This dressing generally only acts as a preservative, since it will only penetrate the rope if it is applied where the rope is bent over a sheave, so that the strands are open enough to allow such penetration. Lubricants are generally petrolatum-based and compatible with similar petroleum jelly type lubricants. 4 DM STANDEN LTD

4 Uncoiling and Unreeling In order to avoid forming kinks in the rope, the following methods are recommended. Measuring Outside Reels - Place a shaft horizontally through the centre of the reel, and raise the shaft after checking that the base is stable. Then pull the free end of the rope in a straight line. Alternatively, the shaft can be vertical, on a turntable, but the former method is preferred. Re-reeling - from one reel to another - avoid reverse bends i.e. feed from top of the fi rst reel to the top of the second, to bottom of the fi rst reel to bottom of the second, but never top to bottom or vice versa. Coils - Place the coil over a turntable, release the ties and pull the free end as above. Alternatively, the coil may be rolled along the ground, leaving the rope lying straight on the ground, although manhandling a long length of wire rope in a coil can be very diffi cult. The diameter of a wire rope is the diameter of a true circle enclosing the rope. Measurement must, therefore, be made across the maximum dimension of a wire rope with an even number of strands i.e. between the crowns of two opposite strands as in Fig. 1 and not with the callipers in contact with 4 strands as in Fig. 2. To be certain that the maximum dimension is measured, the callipers should be rotated around the rope. After a rope has been in use, diameter measurements correctly taken may vary. This occurs when the rope had been braided, or when it has lost its shape due to crushing, or where there has been internal corrosion or damage to the core. In all these cases the cause of the varying diameter measurements should be ascertained. With used ropes some distortion is inevitable, it is recommended that two measurements are taken at right angles to each other which will allow the mean diameter to be calculated. DM STANDEN LTD 5

Sheaves and Drums - Minimum s A sheave, or drum, of too small a diameter will hasten fatigue in any wire rope, and in theory sheaves and drums should always be of large diameter.

5 Sheaves and Drums - Minimum s A sheave, or drum, of too small a diameter will hasten fatigue in any wire rope, and in theory sheaves and drums should always be of large diameter. In practice however designers and manufacturers of machinery often fi nd it necessary to compromise. While, therefore, the table opposite should not be used as sole grounds for modifying a design already implemented, it indicates recommended minimum sheave/drum diameters. Sheave Grooves The rope is supported in the best possible manner if the arc of contact with the groove contour can be 150 degrees. This corresponds to a throat angle of 30 degrees. However, with a large fl eet angle or with oscillating loads, the throat angle should be larger to avoid undue wear of the rope and sheave fl anges. The height of the fl anges should be at least 1.5 times the rope diameter to prevent the rope running off the sheave. A radius 5% larger than half the rope diameter will give the longest service life of the rope. Recommended Minimum Sheave/Drum s Construction 6x7 42 x rope diameter 6x25 Flattened Strand 36 x rope diameter 18x7 34 x rope diameter 6x19 Seale 30 x rope diameter 6x21 Filler 28 x rope diameter 6x19 Filler 25 x rope diameter 6x26 26 x rope diameter 6x31 24 x rope diameter 6x36 22 x rope diameter 8x19 Seale 21 x rope diameter 6x41 20 x rope diameter 8x25 18 x rope diameter Drum Winding The direction in which a wire rope winds on to a drum depends on the direction of the lay of the rope. The diagrams indicate the methods used for Right Hand Lay and Left Hand Lay ropes respectively, together with a useful means of remembering the system, using the right and the left hand. Sheaves and pulleys should be of hard metal. Soft metal is abraded and will wear to the diameter of the wire rope being used, and may also be imprinted with the lay of that wire rope. A new rope will not fi t this imprint exactly, and will therefore, suffer damage. Sheaves should be checked frequently for wear and alignment. Lubrication of sheave and pulley bearings should be maintained. Use the hand to indicate the correct direction, the right hand for the Right Hand Lay rope, and the left hand for Left Hand Lay rope. The closed fi st represents the drum, the thumb indicates the side at which the inside end of the rope is anchored and the index fi nger represents the rope leading off the drum. Most ropes are supplied Right Hand Lay, but some machinery will only accept Left Hand Lay ropes, and if the latter is required it MUST be specifi ed clearly on the order, as Right Hand Lay is always assumed if no lay is indicated. 6 DM STANDEN LTD

Care and Maintenance of a Steel Wire Rope In the interests of both personnel and equipment the advisability of regular and thorough inspection of wire ropes cannot be over emphasised.

6 Care and Maintenance of a Steel Wire Rope In the interests of both personnel and equipment the advisability of regular and thorough inspection of wire ropes cannot be over emphasised. Regular lubrication can make a considerable improvement in rope life before evidence of fatigue appears. The lubricant used should be suitable for the purpose; if in doubt check with the wire rope manufacturer that the lubricant you plan to use is compatible with the dressing applied at the time of manufacture. Do not use solvents to clean a rope before applying lubrication. Paraffi n is not recommended. The recommendations given regarding the running in of anti-spinning types of wire ropes (see right hand side) apply equally to round strand ropes. If broken wires are found in a wire rope these should not be cut off. Grip the broken ends with pliers and bend backwards and forwards until the wire breaks in the gusset between the strands. Loose broken wires out of position can cause rapid break up of adjacent wires. Faulty sheaves are the most common cause of permanent wire rope damage. Make certain all sheaves rotate freely and the treads are in good condition. Check that all sheaves are properly aligned to the path of the wire rope. Misaligned sheaves cause abrasion due to fl ange scrubbing, also rolling of the rope as it settles into the sheave grooves can result in torsional fatigue. When there are two or more layers of wire rope on a drum, the areas of maximum wear are usually where the rope climbs to the next layer and at the crossover point when it scrubs hard against the previous turn. Where terminal attachment permit, a length of wire rope equal to half the drum circumference can be cut from the drum anchorage end to change the position of the wearing sections on the drum. Care must be taken to ensure that there are always two and a half dead turns remaining on a drum with the maximum amount of wire in use. Pressed Aluminium Alloy Ferrule Terminations DM Standen can splice up to 38mm diameter wire rope slings of all constructions using pressed aluminium alloy ferrules. Handling of Anti-Spin Ropes When being reeved on to a machine an anti-spin rope must be handled with care. Unless by prior agreement, anti-spin ropes will always be supplied on reels, and it is recommended they be stored on reels if for any reason they have to be removed from a machine. The most common problem encountered in anti-spin ropes is bird caging, which is caused by: 1. Kinking during fi tting 2. Turn being taken out of over cover of strands (leaving the lay looser) allowing the inner layers to pop 3. Incorrect hand splicing - anti-spin ropes should only be spliced by an experienced and competent splicer trained to splice this type of wire rope 4. Tight or badly maintained sheaves 5. Inadequate or incorrect running-in before normal duty The running in procedure is: 1. Run the rope in and out six times over its maximum working length with a load approximately 25% of the Safe Working Load. 2. Repeat this procedure with the load a 50% of the Safe Working Load, and 3. Continue the same procedure with the load at 100% of the Safe Working Load. Pressed Aluminium Alloy Ferrule Splice Applications Eye with Thimble Eye with Thimble and Ring Eye with Thimble and Link Soft Eyes Eye with Thimble and Shackle Cross-section of a Splice showing how rope and ferrule form one strong, homogenous mass. Eye with Thimble and Hook Longitudinal section of a Splice showing how the metal of the ferrule fl ows round the strands of the rope. DM STANDEN LTD 7

Engineering and General Purpose Ropes Conventional wire ropes, such as those shown listed in the table below, are used in a wide range of applications which include lifting, hoisting, hauling,

Different constructions have different characteristics suitable for a variety of uses depending on design requirements of the strength fatigue resistance wear resistance, fl exibility and abrasion

7 Engineering and General Purpose Ropes Conventional wire ropes, such as those shown listed in the table below, are used in a wide range of applications which include lifting, hoisting, hauling, logging and drilling. Different constructions have different characteristics suitable for a variety of uses depending on design requirements of the strength fatigue resistance wear resistance, fl exibility and abrasion resistance of the wire rope. Wire ropes are available in self colour and galvanised for maritime applications. 6x19, 6x31, 6x36, 6x41 Fibre Core (FC) Steel Core (IWRC) Fibre Core (FC) Steel Core (IWRC) Fibre Core 6x19 Seale + FC x31 Warrington-Seale + FC / x36 Warrington-Seale + FC / Steel Core 6x19 Seale + IWRC x31 Warrington-Seale + IWRC / x36 Warrington-Seale + IWRC / * kn x = tonne 6x41 Warrington-Seale + FC / x41 Warrington-Seale + IWRC / Indent prices available on request 8 DM STANDEN LTD

8 Marine Ropes Marine ropes are galvanised to provide protection against corrosion. The ropes listed below are used in such applications as fi shing, mooring, shipping, lashing and cargo handling operations. Marine/Fishing Ropes - 6x19 Galvanised Small Cords and General Purpose Fibre Core (FC) Steel Core (IWRC) Fibre Core (FC) Steel Core (IWRC) * kn x = tonne Note: The above ropes can be manufactured with PVC covering up to a 44mm outside diameter Marine/Fishing Ropes - 7x7 Galvanised Marine/Yachting Ropes - Stainless Steel Grade 316 Stainless steel and PVC coated wire rope are used when providing protection against corrosion. 7x x Principal Use in Standard Rigging - 1x * kn x = tonne We also stock 3 & 4 strand fishing ropes DM STANDEN LTD 9

Verotop Rope Verotop Lang s Lay rope: is suitable for high lifting applications is a rotation resistant rope made with outer and inner strands compacted has an extremely high breaking strength with

5 10 Design Data Total number of wires: 245 Number of outer strands: 112 Average fi ll factor: 0.74 Average spin factor (1960 grade): 0.81 1960 Grade 2160 Grade 10.0 91.42 97.55 0.510 12.0 131.6 140.

9 Verotop Rope Verotop Lang s Lay rope: is suitable for high lifting applications is a rotation resistant rope made with outer and inner strands compacted has an extremely high breaking strength with very strong resistance to drum crushing is fully lubricated and made of both galvanised and ungalvanised wires should be used with a swivel Discard Number of Wires Length Lang s Lay 6xd 30xd Discard 5 10 Design Data Total number of wires: 245 Number of outer strands: 112 Average fi ll factor: 0.74 Average spin factor (1960 grade): Grade 2160 Grade * kn x = tonne 10 DM STANDEN LTD

Veropro 8 Rope Veropro 8 Regular Lay or Lang s Lay rope: has a plastic layer between the core and the compacted outer strands has a high breaking load and good structural reliability is fully

with a swivel Discard Number of Wires Length Regular Lay Lang s Lay 6xd 30xd 6xd 30xd Discard 18 35 9 18 Design Data Total number of wires: 327 Number of outer strands: 208 Average fi ll factor: 0.

10 Veropro 8 Rope Veropro 8 Regular Lay or Lang s Lay rope: has a plastic layer between the core and the compacted outer strands has a high breaking load and good structural reliability is fully lubricated and made of both galvanised and ungalvanised wires is suitable for multi-layer spooling has very good resistance to drum crushing is a non-rotation resistant rope and should not be used with a swivel Discard Number of Wires Length Regular Lay Lang s Lay 6xd 30xd 6xd 30xd Discard Design Data Total number of wires: 327 Number of outer strands: 208 Average fi ll factor: 0.67 Average spin factor (1960 grade): Grade 2160 Grade * kn x = tonne DM STANDEN LTD 11

Drawing Showing the Component Parts of a Standard Steel Wire Rope

Drawing Showing the Component Parts of a Standard Steel Wire Rope Core wire Rope wire Strand Steel wire rope Core of natural or synthetic fibre or steel * *) The strands are wrapped around a core of fibre