WIRE ROPE 2017

Laying of The Strands (number of wires and position)Fig. 3 6 19 StrandOne strand is normally made up of seven to several tens of wires with similar, or differing, diameters in single or multi-layers.In the method where the wires are positioned toform more than two layers, there is the cross laywhere the wires of each layer are in the same layangle, and the parallel lay where one process isused to lay the wires so that the wires of each layerwill be of the same pitch.For strands of the same diameter, the more thenumber of wires, the smaller will be the diameterof each wire and the greater will be the flexibility ofthe strand. However, conversely, the rope willbecome inferior in its wear resistance nature andits shape deformation nature.Point Contact LayFig. 4 Cross sectional view example of strand in the cross lay rope(1)Cross LayThe cross lay is referred to as the point contactlay, as each wire is in contact with each other. Thelaying of the wires are carried out in such a waythat the lay angle will be almost equal for eachlayer of wire of the same diameter. The length ofthe wires in each layer will also be the same andthe wires of each layer will be in contact with eachother.Therefore, the tension stress which works on thewire will become uniform, but the bending stressdue to the contact points will be added and so thefatigue resistance will not be as great.Moreover, the 6 7, 6 19 and 6 24 belong tothis lay method.In the positioning of the wires, there is themethod where the number of wires around a singlecore are increased in units of six each, or progressively from 6 to 12 to 18 to 24 and the methodwhere three wires are stranded and made into a coreand around this the number of wires increased bysix each for each layer, or 9 to 15. Normally, theformer positioning is over whelmingly the most,while the latter is seen only for the 6 24 strand(a 9 15) where the three wire core is replacedwith a fibre core.106 196 246 376 61

Outline of Wire Ropes(2)Parallel LayParallel lay is also referred to as equal lay. It isalso called one operation lay from the number ofstranding processes and also as linear contact layas each wire is in contact with each other.Moreover, at this company, the parallel lay ropehas the product name of Super Rope.In the parallel lay, the wires of each layer arepositioned in such a way that there will be nospace between them and so that the upper layerwires will fit neatly into the groove of the lowerwires of the strand.For this, wires of dif fering diameters arepositioned at the same time so that each wire layerwill have the same pitch and will be in contact witheach other.Therefore, dif fering from the cross lay rope,although the lay angle of each wire layer and thelength of the wires are not uniform, as each wire isin contact with each other, it is superior in itsfatigue resistance nature.Moreover, the 6 Fi(25), 6 WS(36) and the 8 S(19) belong to this lay method.Fig. 6 Cross sectional view example of strand in parallel lay ropeSeale type6 S(19)Warrington type6 W(19)Filler type6 Fi(25)Warrington Seale type6 WS(36) Basic typesAs the basic parallel lay, there are the followingfour types.(a)Seale typeThe number of wires of each layer is shown as1 n n and the number of wires of the inner andouter layers is the same.The wires of the outer layer fit completely intothe grooves of the inner layer wires. The outerlayer wires of this Seale type rope is thicker whencompared to other parallel lays and so it issuperior, particular in its wear resistance and ismainly used for elevators.(b)Warrington typeThe number of wires of each layer is shown as1 n (n n) and there are two kinds of wires forthe outer layers, one being large and the othersmall. The number of wires of the outer layer isdouble that of the inner layer and through acombination of the inner and outer layers thespaces between the wires is kept small.This Warrington type rope is not being used toany great degree, recently.(c)Filler type (with filler wire)The number of wires of each layer is shown as1 n (n) 2n and the number of wires of theFig. 5 6 Fi(25) strandLinear Contact Lay11

outer layers is double that of the inner layer.The inner wires and the same number of thinfiller wires are used to fill the spaces in the innerand outer layers.This filler type rope has a good balance betweenthe flexibility, fatigue r esistance and wearresistance and has the widest range of use amongparallel lay ropes.(d)Warrington Seale typeThis is a combination between the Warringtontype and the Seale type and is extremely superiorin its fatigue resistance nature. It also abounds inflexibility and is superior in its wear resistancenature and so has a wide range of uses.Fig. 7 Cross sectional view example of strand in aflat type rope(3)Flat TypeThe strands are combined in such a way that theouter circumference of the rope will be flat inshape. This rope has a smooth surface and so thesurface pressure due to coming into contact withthe groove of the drum and the sheave is smallerthan that of ordinary ropes. It is also superior inits wear resistance nature. In general, the triangularstrand and the shell strand are used the most. Theflat strand is also being used at certain places.(a)Triangular strand typeUp to now, an outer layer wire was positionedaround the triangular wires but, recently, a singlelayer or two layers of wires are stranded around atriangular core made of round wires to form around wire triangular core strand.(b)Shell strand typeThe cross sectional view of this type is in theshape of a shell and this rope is usually in threestrands, or four strands.Also, apart from the fatigue resistance nature, italso has a non-twisting nature. The Mono-Rope ofthis company which is being widely used belongsto this type.Shell strand typeMono-Rope4 F(30)Triangular strand typeFlat type6 F [(3 2 3) 7]12

Outline of Wire Ropes Rope CoreThe rope core can be classified into the fibrecore and the steel core.This core rope is positioned in one process withthe outer layer rope. Moreover, for the core rope,the 7 7 and the 19 8 7 are used.The IWSC and the CFRC are used in only a fewspecial cases. Among ropes with a steel core, theIWRC has a good flexibility and so is used themost.The characteristics of the steel core are asfollows compared to the fibre core.(a)The tope has a high strength.(b)Resists lateral pressures and does not becomedeformed easily.(c)The elongatior of the rope is small and thechange of diameter is low.(d)The rope has a superior heat resistance nature.(1)Fibre core (abbreviated as FC)The fibre core has two important functions, or ①to support the strand and at the same time to holdthe shape of the rope, and ② to hold the ropegrease and to supply the necessar y amount ofgrease to the inside of the rope, during use, forlubrication and to prevent corrosion. In the past,natural fibre was mainly used but, of late, syntheticfibre is starting to be used.Two kinds of natural fibres are used, one beingthe hard fibre, such as Manila and saisal , as wellas jute and the other being the soft fibre, such ascotton threads, used in ropes with a comparativelysmall diameter. Also, for synthetic fibre, speciallyprocessed polypropylene is used so that the synthetic fibre will hold the grease well.The characteristics of fibre core compared tosteel core are(a)The rope has a high flexibility.(b)Impacts and vibrations to the rope are absorbed.(c)Holds rope grease well (in par ticular, in thecase of natural fibre)(d)The unit and mass of the rope is small.Moreover, synthetics fiber compared to naturalfibre is superior in its corrosion resistance nature.Fig. 8 Cross sectional view example of a steel coreropeIWSC7 19(2)Steel coreFor steel cores, there is the strand core (IWSC)and the rope core.Among the rope cores, there is the IWRC andthe CFRC.(a)The IWSC (independent wire strand core) hasthe strand as the core and those that have thesame construction as the side strand are referredto as the common core.(b)The IWRC (independent wire rope core) has asingle independent rope as the core. Usually, a7 7 construction is used but depending on theuse a 6 7 or a 6 19 may be used.(c)For the CFRC (center fit wire rope core), theouter layer strand of the core rope is fitted into thegroove of the inside of the side strand of the rope.IWRCIWRC 6 Fi(25)13CFRCCFRC19 8 7 8 Fi(25)

Type of lay(1)Direction of layAs concerns the direction of laying the rope andthe strand, there is the Z lay and the S lay, asshown in Fig. 9.In the case otherwise specified, the rope shall bemade of the Z lay and the strand products of the Slay.Fig. 9 Type of lay(2)Laying of ropeIn laying of rope, there is the ordinary lay andthe Lang’s lay.(a)Ordinary lay (or regular lay)The lay of the rope and the lay of the strands arein opposite directions.(b)Lang’s layThe lay of the rope and the lay of the strands arein the same direction.(c)Comparison of the characteristics by layingof ropeThe dif ferences in the characteristics whichinevitably arises from the differences in laying ofrope are as shown in Table 1.Table 1 Comparison of the characteristics by laying of ropeItemsOrdinary layLang’s layAppearanceThe wires are approximately parallel to theaxis of the rope.The wires form a certain angle with the ropeaxis.MeritsKinks do not form easily and is easy to handleThe lays are tight and the form does notcrumble.The wires appearing on the surface are longand superior in wear resistance. Flexible andhas good fatigue resistance nature.DemeritsInferior in wear resistance nature and fatigueresistance nature compared to the Lang’s lay.The rope has a large torque and forms kinkseasily.14

Outline of Wire Ropes Preforming Kinds of CoatingPreforming is a method for lessening the springiness of the rope by giving each strand and wire afor m in advance. Ropes made through thismethod are called preformed, or Tru-lay ropes.The strands and wires do not fall apart even whenthe rope is cut.The ropes being manufactured, at present, arepractically all preformed ropes. Apart from the6 61, the non-preformed ropes are only for specialuses.Ropes are usually of the bright type but when acorrosion resistant nature is required the ropesare coated.Among the kinds of coating, there is the zinccoating and aluminum coating. Generally however, the zinc coating is used.Apart from the general hot dip galvanizing, thiscompany is using a high corrosion resistant alloycoating with zinc and aluminum, under the productname ZINCAL through a high speed coatingmethod.Both are receiving high evaluation for theirsupe-rior corrosion resistant nature.Apart from these, this company can make ropeswith a special coating, on request. Breaking Force (Grade)For the breaking force, there is the designatedbreaking force and the actual breaking force. Thedesignated breaking force is the standard value, orthe lowest value of the breaking force, while theactual breaking force is the lowest value at thetime the test pieces break.The breaking force is determined by the nominaltension of the wires making up the rope and isclassified as shown in Table 2.Apart from these, this company will make ropesthat exceed the strengths shown, on request.Table 2 Grade of Wire ripeGradeRemarksGrade E (1320N/mm2  {135kgf/mm2 } class)Bright and galvanizedGrade G (1470N/mm2  {150kgf/mm2 } class)GalvanizedGrade A (1620N/mm2  {165kgf/mm2 } class)Bright and galvanizedGrade B (1770N/mm2  {180kgf/mm2 } class)Bright and galvanizedGrade T (1910N/mm2  {195kgf/mm2 } class)Bright(Note) (1)   Wires cold worked after galvanizing shall not exceed 2.80 mm in diameter.(2)   Wires cold worked after galvanizing shall not exceed 2.24 mm in diameter.15

Lubricating Rope DiameterRope grease is applied to the rope at the time ofmanufacture to prevent cor rosion and also toprovide lubrication. Great care is taken to applythe rope grease uniformly and so that it willpenetrate to the core and strand, through animpregnation method.The kind of grease applied will greatly influencethe life of the rope.Table 3 below shows the number of bendingsbefore a breaking arose, according to a fatigue testcarried out by this company.Among r o pe gr e ases, ther e ar e the noncr ystalline grease such as the Petrolatum andMicro Wax and the r ed rope gr ease whoseprincipal ingredient is a special wax made up ofmicro cr ystals, as well as the black rope greasewhoe principal ingredient is a special kind ofbitumen, such as asphalt.This company has manufactured a special ropegrease that is superior in its r ust prevention,lubrication, stability and safety.Among rope diameters, there is the nominaldiameter and the actual diameter (diameteractually measured) and, in principle, for JIS G 3525(referred to as JIS herein) the standard number(JIS Z8601) is employed. On the other hand, asshown in Fig. 10, the actual diameter is themeasurement of the circumscribed circumferenceand is expressed in mm.The tolerance on rope diameter shall be 100 % forthe diameter less than 10mm and 70 % for that equalto or more than 10mm, according to JIS.This company is making ropes with a diameterof up to 200mm, depending on the construction ofthe rope.Fig. 10 Measurement of rope diameterTable 3 Comparison of the fatigue characteristics of therope, according to Lubricated or unlubricatedS bend fatigue : 6 Fi(17) O/L 18mmφ Grade Bbreaking force 20.7tf) D/d 28 Tension : 2.6tfGreaseconditionRightWrongNumber of repeat bendingUp to the firstbreakageUp to 10% wirebreakage per ubricatedunlubricated2.052.15 LengthThe length of the rope is generally set at 200m,500m and 1,000m but a longer length can be madeon request.On the other hand, ropes that weight up to 120 tonsare being made, depending on the construction ofthe rope.16

Outline of Wire Ropes Designation and SymbolThe rope is referred to in terms of construction,laying of rope, lay direction of lay, whether nakedor galvanized, the kind of rope grease, diameter,grade, breaking force, length and reels. Expressingthese in words and numbers would make thedesignations too lengthy and complex and so thiscompany is using the following symbols.(1)ConstructionKind of core Number of strandsLay symbol of the strandNumber of wires per strand(See Table 5)(See Remarks)(See Table 4)Moreover, in the case there is a product symbol,the symbol is placed at the front (for example, thisis T in the case of Tough-Rope).Table 4 Symbol for the kind of coreKind of coreSymbolRemarksFibre coreUsually not usedRefer to designation examples 1 and 2Strand coreUsually not usedIn the case the construction of the core strand differsfrom that of the strand for the rope itself, a symbol isused for expressing this construction (see example 3).In the case the construction is the same, in place ofshowing IWSC, this is shown as “the number ofstrands of the rope itself 1” in the “number ofstrands” column (see example 4)Rope coreIWRC(Independent Wire Rope Core)orCFRC(Center Fit Wire Rope Core)In the case the core rope is other than 7 7 thecomposition is also shown (see example 5) and inthe case the core rope is 7 7 the construction of thecore rope may be omitted in the parentheses (seeexample 6).Table 5 Lay symbol for strandLay methodSymbolCross layParallel layGeneralFlat typeSeal typeWarrington typeFiller typeNo symbolFSWFiWarringtonSeale typeWS(Note)   The total number of wires per strand is shown but of the flat type rope, apart from the Mono-Rope, the triangular strand rope is disassembled and expressed (see example 7). Designation examples1. 6 7, 6 19, 6 24, 6 372. 8 S (19), 6 WS (36)3. WS (36) 8 S (19)4. IWSC 6 37 ― 37 6 37 ― 7 375. IWRC (6 19)8 WS (36)6. IWRC (7 7)6 Fi (25) ― IWRC 6 Fi (25)7. 6 F [(3 2 3) 12 12]17

(2)Laying of rope, etc.The direction of lay and whether galvanized, ornot, and the kind rope grease used are abbreviatedin Table 6.Table 6 Abbreviation of laying of rope, etc.Ordinary layLayZ layKind of rope greaseBright orGalvanized(Remarks) 1.2.3.4.Lang’s layS layZ layS LSGC/LSLaying of rope: The Lang’s lay is shown as L and the ordinary lay as O.Direction of lay : In the case of the Z lay, no symbols are used while in the case of S lay, S is used.Bright or galvanized: In the case of naked, no symbols are used, while in the case of galvanized the letter G is used.Kinds of rope grease: Black rope grease is shown as C, while red rope grease is shown as O. However, in the case pf galvanized ropes,the O is omitted. Moreover, in the case of the slip prevention grease, V is used and for fishing industry use the letter T or TN is used.(3)Grades (breaking force)grade E, grade G, grade A, grade B grade T orbreaking force are expressed in “kN” or “tf ”.(4)DiameterThe rope diameter is expressed in “mm”.(5)LengthThe rope length is expressed in “m”.(6)Rope designation examples(a) 6 strands of 19 wires, fibre core, naked, redrope grease, ordinar y lay, Z lay, Grade A, ropediameter 20mm, length 500m, 2 reels, shown as:6 19 O/O 20mm Grade A 500m 2(b) 6 strands of 37 wires, fibre core, galvanized,red rope grease, ordinary lay, Z lay, Grade G, ropediameter 16mm, length 200m, 5 reels 6 37 G/O16mm Grade G 200m 5(c) Filler type 6 strands of 29 wires, rope core,galvanized, black rope grease, Lang’s lay, S lay,Grade B, rope diameter 30mm, length 1,500m, 1reel as: IWRC 6 Fi(29) GC/LS 30mm Grade B1,500m18

Wire Rope Standard1 Cross Lay Rope The cross lay rope construction has the longesthistor y and, until the 1930s, when this companywas established (and the domestic manufacture ofrope was started) and the parallel lay rope, or thesocalled seale type was developed, only the crosslay rope was used. With the appearance of theparallel lay rope, the cross lay rope gradually wasreplaced with the parallel lay rope. However, asthe cross lay ropes had some merits which theparallel lay rope did not, such as the ease of handling, it is still continuing to be used, at present. Main Types and UsesConstruction symbolMain uses6 7Lift stay ropes, main rope for ropeways, tugboat use, winch rope for pits and inclinedmine shafts, guide rope for digging shafts, trawler use, stay rope (including ship use)6 19Forestry industry use rope, winch rope for pits, trawler use stay rope (including ships),boring use, winches and other various kinds of machines.6 24Loading and unloading using cranes, etc. Rope Sling fixed shore fishing nets, fisheriesindustry use such as environment, elevator use, mooring ropes, tow rope, ship use suchas cargo ships, winches and other machinery.6 37IWRC 6 37Loading and unloading using cranes

⑦ Cable Laid Rope / 69〜70 ⑧ Locked Coil Rope (for rails) / 71〜80 ⑨ ZINCAL Rope / 81 Rope End Processing 82〜92 ① TOYO-LOK / 82〜85 ② SINGLE-LOCK (Swage Socket) / 86〜91 ③ Socket Processing / 92 Rope End Metal Fittings 93〜99 Reference Charts 100〜103. 1 .