Wire Rope Inspection

®

Wire Rope Inspectionand Examination

1R. Verreet & W. Lindsay, Wire Rope Inspection and Examination, 1996

Wire Rope Inspectionand Examination

FOREWORD

In the UK two Codes of Practice deal with the Inspection and Examinationof steel wire ropes, B.S.7121: Part 1 1989 „Safe use of Cranes“ and B.S.6570 : 1986 „The selection, care and maintenance of steel wire ropes“.

B.S. 7121 deals specifically with cranes, much of the information it containsrelating to ropes has been taken from B.S.6570. However, B.S.7121 doeshave additional useful information about the discard criteria to be appliedwhen assessing the condition of a rope.

B.S.6570 is a comprehensive Code of Practice and gives information on theselection, care, maintenance, inspection and examination of general pur-pose ropes.

by Dipl.-Ing. Roland Verreetand William Lindsay

1. Why must wire ropes be inspected and examined? ............ page 22. What is Inspection, what is Examination? ......................... page 33. When must wire ropes be inspected? ................................ page 44. When must wire ropes be examined? ................................ page 45. Survey for removal criteria ................................................ page 66. Where must wire ropes be inspected or examined?............ page 107. Discard number of wire breaks ......................................... page 128. Rope examination procedure ............................................. page 138.1 Equipment ........................................................................ page 138.2 Locating of wire breaks ..................................................... page 138.3 Determination of the rope diameter ................................... page 158.4 Measuring rope lay ........................................................... page 178.5 Checking the stability of the rope ...................................... page 188.6 Changes in rope structure ................................................ page 188.7 Inspecting sheaves and drums .......................................... page 189. Electro-magnetic wire rope examination ............................ page 20

2 R. Verreet & W. Lindsay, Wire Rope Inspection and Examination, 1996

100

~100%

breakdiscardnumber of cylces [ % ]

actu

al b

reak

ing

load

[

% ]

00

1. Why must wire ropes beinspected and examined?

Wire ropes are consumable itemswith a limited life. During servicethe physical properties of a wirerope will change.

At the commencement of service,the individual wires and strandssettle into position and the ropebreaking strength increases. Af-ter reaching a maximum it de-creases rapidly (Fig. 1).

This decrease in breakingstrength is caused by the pro-gressive loss of the metalliccross-section due to abrasionand corrosion, by wire breaks

Fig. 1

and by changes in the structureof the rope.

A chain represents a series con-nection of load bearing elements.If only one link in the chainbreaks, the whole lifting devicewill fail completely. A wire roperepresents a parallel connectionof load bearing elements and con-sequently it can still be operatedsafely after one or more wirebreaks.

Generally, there is a steady rateof increase in the number of wirebreaks during the life of the rope.Fig. 3 shows the increasing num-ber of wire breaks as a function ofthe number of cycles in a bendingfatigue test.


2. What is Inspection,what is Examination?

An inspection is a careful and cri-tical assessment of the rope andfittings carried out without dis-mantling.

An examination is a careful andcritical assessment of the ropeand fittings carried out by a com-petent person. This should in-clude, where necessary, a visualassessment of the internal condi-tion of the rope, supplemented byother means such as measure-ment and non destructive test-ing. In order for end fittings to beexamined properly they mayneed to be dismantled.

Fig. 2

chain, oneelement broken

One of the objectives of inspect-ing and examining a wire rope isto supervise the normal processof deterioration so that the ropecan be removed from service be-fore becoming a hazard to safety.Another benefit of the inspectionand examination procedures is todetect unexpected damage orcorrosion.

Inspections and examinations,properly carried out, ensure thediscard of a rope before failure. Inaddition, precautions can be ta-ken to avoid a recurrence of dam-age or excessive wear to futureropes.

rope, oneelement broken


When a rope has been removedfrom equipment and later fittedto the same or different equip-ment, it should be inspected afterfitting but before resuming serv-ice.

If at any time a change in the ropecondition is suspected, it shouldbe reported immediately and theequipment taken out of serviceuntil the rope has been examinedby a competent person. As a re-sult of this examination it may beprudent to review and amend thescope and frequency of the in-spections.

3. When must wire ropesbe inspected?

Wire ropes should be inspected atthe start of each shift, work pe-riod or more frequently, depend-ing upon past experience. Usu-ally this inspection will be carriedout by the operator of the indi-vidual piece of equipment or pos-sibly by a member of the workforce specially appointed.

The inspection should be a visualassessment of the condition of asmuch of the rope length as possi-ble, including the points of at-tachment to the equipment.

Fig. 3

30

25

20

15

10

5

00 30.000 60.000 90.000 120.000

num

ber

of

bro

ken

wir

es o

n 3

0 x

d

[ –

]

tensile strength 180 kp/mm2

load 100 %

tensile strength 200 kp/mm2

load 111 %

number of cycles [ – ]

D/d = 20load proportional tominimum breaking load


4. When must wire ropesbe examined?

The Factories Act 1961 Section26, The Construction (Lifting Op-erations) Regulations No. 1581and the Offshore Installations(Operational Safety, Health andWelfare) Regulations 1976 No.1019 all require a thorough ropeexamination at least once in eve-ry period of six months.

The Shipbuilding and Ship-re-pairing Regulations 1960 requi-res a thorough examination everythree months or monthly afterthe first broken wire has beendiscovered.

One of the statutory regulationslisted above will apply to the loca-tion and type of rope using equip-ment being examined.

It is the responsibility of the indi-vidual to institute and maintain aprogramme of periodic examina-tion which satisfies the require-ments of the appropriate regula-tions and the specific operatingconditions of the equipment.

Examination should be carriedout at regular intervals. The in-tervals should be scheduled sothat any damage will be detectedearly.

According to B.S. 6570 examina-tions should be carried out “atregular intervals, the frequencyof which will be influenced by thefollowing:

a) statutory requirementsb) type of appliance and/or

design of the systemc) operational environmental

conditionsd) method and frequency of

operatione) manufacturer’s recommen-

dationsf) results of previous inspec-

tions and examinationsg) experience with previous

ropes on the appliance orsystem”

During the first few weeks afterthe installation of a new rope thedaily inspection can be used tomonitor performance as the ropemight have been fitted incorrectlyor the type of rope might not besuited to the equipment.

The intervals between the exami-nations should also be reducedafter the first broken wire orother damage has been detected.

If the rope has been overloaded orif non- visible damage is sus-pected, the intervals between ex-aminations should be reducedaccordingly.

Moreover, the examinationsshould be carried out when therope is put back into service afterlong periods of standstill.

If a lifting device has been dis-mantled and re assembled, therope must be examined before itis allowed to operate again.


5. Survey of removalcriteria

A wire rope must be removed ifone or more of the following crite-ria can be satisfied:

1) Broken wires.

A wire rope must be discarded ifthe permissible number of wirebreaks is reached or exceeded. Itmust also be replaced when localconcentrations of wire breaks oc-cur.

Chapter 7 covers in detail thesubject of the permissible num-ber of wire breaks according toBritish Standard 6570 and thestatutory requirements.

2) Reduction in diameter.

Reduction in diameter can becaused by abrasion, corrosion ora local failure of the rope core.According to B.S. 6570 a wirerope should be discarded „whenthe rope diameter anywhere is re-duced to 90% of the nominal di-ameter in the case of six andeight strand ropes“. Consideringthe fact that a rope is allowed tohave an oversize of 4% when new,this figure would allow for a di-ameter reduction of 14%, whichseems to be excessive.

For multi- strand ropes B.S.6570 recommends a detailed ex-amination “if the rope diameter

falls to 97% of the nominal, orrises to 105% of the nominal”,because “discard may be neces-sary”.

3) Corrosion.

Corrosion may be external or in-ternal, general or localized. Ac-cording to BS 6570, a wire ropeshould be discarded “when thesurface of the wires is severelyroughened or pitted, or if thewires are slack within thestrands due to wastage”.

4) Rope deformation

a) Waviness (Fig. 4a). This defor-mation, while it may not neces-sarily affect the strength of therope, can transmit pulsation andproduce uneven rope wear. Whenthe rope is laid on a level surfaceunder no load, the maximumheight of the “wave” should notbe greater than the nominal ropediameter + 1/3, otherwise therope should be removed fromservice.b) Birdcage (Basket Deformation)A birdcage (Fig. 4b) developswhen the outer layer of strandsbe comes longer than the innerlayer or layers. The conditionmay occur as a result of incorrectfitting, tight sheaves, shock load-ing, incorrect use of a swivel orthe application of a heavy load toa new rope before the strandshave settled into position. Ropeswith a birdcage should be dis-carded.


a

Fig. 4

c) Loop Formations. Wires orgroups of wires may form a line ofloops parallel to the axis of therope (Fig. 5a). This deformation isoften caused by shock- loading.Loop formations are a justifica-tion for discard.

d) Loose Wires. Where loose outerwires (Fig. 5b) are found withoutany adjacent mechanical dam-age, the most likely cause will becorrosion and the rope should beremoved from service. Where

loose wires have been caused bymechanical damage, a full exami-nation will decide if the rope canremain in use.

e) Nodes (Fig. 5c). A node is alocal increase in rope diameterwith the core easily visible be-tween several covering strands. Itcan be caused by shock loadingor, in the case of fibre main coreropes, by the absorption of mois-ture. A node is a justification fordiscard.

b


Fig. 5

f) Thinning of the rope (Fig. 6a).Thinning is a reduction in the di-ameter of the rope over a shortlength. It is often associated witholder fibre cored ropes usually inareas of sustained heavy loadsover sheaves. The disintegrationand loss of the core can allow oneof the covering strands to takethe place of the core. When thiscondition occurs in ropes withIWRC the distortion will most of-

ten be in the vicinity of the termi-nation away from drum. Themost likely cause is rope rotationwhich has allowed the rope tounlay, resulting in the overloadand reduction in diameter or fail-ure of the IWRC.

g) Misplaced Outer Wires. Mis-placed outer wires are wiresforced out of position along theline of the rope to form small flat-

c

a

b


tened loops. This can be causedby bad drum spooling or by therope being drawn across a sharpedge. Langs lay ropes are oftenworst affected. Misplaced outerwires are a justification for dis-card.

h) Kinks (Fig. 6b). Deformationcaused by a loop in a rope beingtightened when the rope cannotrotate about its axis to release the

torque. The tight bend or kinkthus formed can result in a seri-ous loss of strength due to un-balance in the lay lengths. Ropeswith kinks must be discarded.

i) Flat areas (Fig. 6c). A flatteningcan be caused by bending therope severely over the rim of asheave or any sharp object withthe wires on the inside of thebend being forced out of position.

Fig. 6

a

b

c


220

180

160

120

100

80

60

0 100 200 300 400 500 600 700temperature [ °C ]

tensi

le s

tren

gth [ k

p/m

m2 ]

140

200

Ropes with flat areas should bediscarded.

5) Damage caused by heat.

Heating rope wires to approxi-mately 300° C and over will leadto considerable reduction in ten-sile strength of the wires (Fig.7).Wire ropes which have been sub-jected to excessive heat must bediscarded.

6. Where must wire ropes beinspected or examined?

During an inspection or a peri-odic examination by a competentperson, the full length of the rope

should be checked.

The following areas may requiremore detailed attention:

a) Rope zones with the highestnumber of cycles. During normalday to day operations some sec-tions of a rope length will suffer agreater number of bends oversheaves and drums than others.It is in these areas where thegreatest number of fatigue wirebreaks can be expected.

b) Pick- up points. When a liftingdevice picks up or releases a loadwith the same sections of roperegularly in contact with sheavesand drums, those sections of therope are subjected to increased

Fig. 7


stress.

c) End fittings. At, or closely adja-cent to, terminal fittings the elas-ticity of the rope is restricted andthe geometry “frozen”.

Depending upon the type of fit-ting, there will be additional pres-sure on the rope and the sectionclose to the area of contact be-tween rope and fitting is often thefocal point for increased stresscaused by vibration.

The danger of corrosion is alsoincreased by the retention ofmoisture in the area of contactbetween rope and fitting.

d) Equalising sheaves. Ropeswhich are often considered to bestationary around equalisingsheaves can be subjected to highnumbers of bend cycles causedby the uneven spooling of twodrums, by swinging loads or byfrequency vibrations. As the ropemight never leave the equalisingsheave, moisture can be trappedin the area of contact betweenrope and sheave and cause corro-sion.

e) Zones of maximum wear ondrums. Pick- up points andcross- over points on the drumare subjected to increased wearand therefore require special at-tention. Misplaced and brokenwires caused by scrubbing can beexpected at cross- over points.The damage can be severe where

the fleet angle is excessive.

With multiple layer spooling, thefirst layer of rope on the drumshould be tightly wound to pro-vide a firm base for subsequentlayers. This applies in particularto plain drums and parallelgrooved drums, e. g. Lebus. Slackwinding or lateral movement be-tween turns of rope will affect thespooling of subsequent layersand can cause damage.

The point where the rope issqueezed between the drumflange and the previous turn as itrises to commence the next layer,is an area of accelerated wear andshould be given special attention.

f) Sheaves. Sheaves should be ex-amined for general condition andtested for freedom of movement.Using a groove gauge the treadradius can be measured.

The radius of the grooves shouldbe equal to the nominal rope di-ameter plus + 6% to + 10%.

Undersize grooves will seriouslyreduce the service life of the ropedue to the effects of crushing.Oversize grooves reduce the serv-ice life due to premature fatiguecaused by insufficient support inthe groove area.

Where the rope surface pattern isimprinted into the sheave tread,the sheave should be replaced.


g) Rope sections working in ahostile environment. High tempe-rature can considerably reducethe breaking load of a wire rope.Temperatures of up to 250°C willnot affect the tensile strength ofthe wire, but temperatures ofonly 50°C can cause leaching ofthe rope lubricant.

The consequent severe wire towire friction will result in a mar-ked reduction of rope perform-ance. The exposure of rope tochemical action can greatly in-crease the effect of corrosion.

In each of the areas where wirebreaks or other defects are found,the number and descriptionalong with the location, must berecorded.

7. Discard number ofwire breaks

The Construction (Lifting Ope-rations) Regulations requires arope to be replaced when thenumber of broken wires reaches5% of the total number of wires inthe rope in 10 x d.

The Factories Act, The Shipbuild-ing and Ship-repairing Regula-tions and the Offshore Installa-tions Regulations do not specify aparticular number of brokenwires for discard and leaves thisdecision to the discretion of theexaminer.

The Health and Safety at WorkAct requires the provision andmaintenance of plant and sys-tems of work that are, so far as isreasonably practical, safe andwithout risks to health.

The table on Page 25 shows therecommended number of discardwire breaks for CASAR specialwire ropes. For the number ofdiscard wire breaks in othertypes of multi-strand ropes theuser is advised to contact therope manufacturer.

Depending on the factor of safety,the assessment of broken wiresin 6 and 8 strand ropes workingover steel sheaves is divided intotwo groups :

1) Factor of safety less than 5 :5% of the number of outer strandwires excluding Filler wires.

2) Factor of safety greater than 5 :10% of the number of outerstrand wires excluding Fillerwires.

When broken wires are detected,the number and position, alongwith the examiner’s opinion ofthe general rope condition, willdecide whether or not the ropeshould be discarded.

If local concentrations or groupsof broken wires are found, therope should be discarded when:


should be available:

a list of the discard criteria (this manual)a rope caliper or vernier gaugea steel tapea piece of white chalka wax pencil (dark coloured)a roll of adding machine papera sheet of typing carbon papera screwdrivera magnifying glassa pencila roll of marking tapetwo sets of groove gaugesa piece of cleaning clotha wire brusha pair of glovesa note book or an inspection formthe previous inspection records

8.2 Locating of wire breaks

Identification of wire breaks canbe by visual and physical exami-nation or by the use of electroma-gnetical equipment (see sec-tion 9).

The first step in wire rope exami-nation is to find the rope sectionwith the greatest concentration ofwire breaks. This is normallydone by first visually inspectingthe full length of the rope.

In some cases it can be helpful tospool the rope slowly through thehand. Special attention has to bepaid and strong protective glovesmust be worn.

a) three or more broken wires arefound in the close proximity ofthe termination,

b) three or more broken wires arefound in one strand or

c) five broken wires are found be-tween two adjacent strandswithin a length of 10 x ropediameter.

If the number of broken wiresdoes not justify discard, the posi-tion and number of all brokenwires found must be recorded inthe rope examination Log Book.

When broken wires are found inclose proximity to a permanenttermination, such as a white me-tal or resin secured socket andthe general condition of the re-mainder of the rope is acceptable,it may be decided to cut the ropeand re make the termination. Insuch cases it is recommend thatthe socket is submitted for N.D.T.and heat treatment. Care mustbe taken to ensure sufficientturns of “dead” rope remain onthe drum after the terminationhas been remade.

8. Rope examinationprocedure

8.1 Equipment

In order to carry out a proper in-spection, the following tools


A piece of wood held on the sur-face of a moving rope will be de-flected by the protuding ends ofbroken wires. In the same way, asoft cotton or similar type clothheld against a moving rope will becaught by protruding ends andthus detect the broken wires.Smooth synthetic material is lesssuitable for this purpose.

The detection of broken wires inthe strand valleys can be diffi-cult. The use of a scraper or pieceof shaped wood will help cleanout the valleys. The use of a wirebrush on a dirty, heavily lubri-cated rope can loosen, but not

Fig. 8

always remove, old lubricant andthe brush may have to be cleanedfrequently with a solvent.

Where solvents are used to cleanthe rope surface, they should beused sparingly and the rope sec-tion should be thoroughly lubri-cated afterwards. A light lubricat-ing oil used with a wire brush ispreferred for softening old lubri-cant which can then be wiped offwith a cloth. When the worst af-fected sections of rope have beenfound, their boundaries shouldbe marked by chalk or tape forfurther examination.


A gauge should be set to a lengthof 10 x d. This can now be movedwithin the boundaries to locatethe section with the maximumnumber of wire breaks. Thebreaks in 10 x d should be coun-ted and entered in the records.

With thin ropes, valley breakscan be detected by strongly flex-ing the unloaded rope (Fig. 8).

8.3 Determination of therope diameter

The rope diameter should bemeasured on receipt for conform-ity with the specification. BritishStandard (B.S. 302:1987, Stran-ded steel wire ropes, Part 1.Clause 5.1) allows for a toleranceof - 1% to + 4% of the nominalrope diameter.

The generally accepted method ofmeasuring rope diameter forcompliance with the Standard isto use a caliper with jaws broadenough to cover not less than twoadjacent strands. The measure-ments must be taken on astraight portion of rope at twopoints at least 1 metre apart. Ateach point two diameters at rightangles should be measured. Theaverage of the four measure-ments is the actual diameter.

After the rope has made the firstfew cycles under low load, therope diameter should be meas-

ured at several points. The aver-age value of all the measure-ments at each point must be re-corded and will form the basis ofcomparison for all future meas-urements.

The measurement of the rope di-ameter is an essential part of allinspections and examinations. Itensures the maximum diameterreduction does not exceed therecommended figure. As stated in5.2. British Standard 6570 re-commends that a wire ropeshould be discarded when the di-ameter of the rope is reduced to90% of the nominal diameter.

A comparison of the measureddata with the recorded previousvalues can detect an abnormalrate of reduction in diameter.Coupled with assessment of pre-vious rope examination data, theprobable date of rope renewal canbe predicted.

If we examine the cross-section ofa six-strand wire rope, we willfind that measuring the thick-ness of the rope over the crowns(Fig. 9a) will produce a higher va-lue than measuring it over thevalleys (Fig. 9b). The actual diam-eter of the rope is defined as thediameter of the circumscribingcircle.

When using a conventional ca-liper, wire ropes with an evennumber of outer strands (four-,six-, eight-, ten-, and multi-


strand) ropes must be measuredfrom crown to crown. The advan-tage of a proper wire rope caliperwith measuring plates is thateven if the measurement is car-ried out “incorrectly”, adjacentcrowns are always included, sothat the actual diameter is deter-mined at any section (Fig. 10).

Measuring the diameter of wireropes with an uneven number ofouter strands (three-, five-, se-ven, or nine-strand ropes) is mo-re complicated: a crown on theone side of the wire rope alwayshas a valley as a counterpart onthe other side of the wire rope. A

Fig. 9

conventional caliper, therefore,has to be applied diagonally tothe axis of the rope, so that at anytime a crown adjacent to a valleyis covered. Again a wire rope ca-liper with measuring plates isdefinitely to be preferred as it al-ways includes strand crowns.

In all cases during periodic ex-aminations where the measure-ments are to be recorded, therope should be measured as al-ready described. Where the„roundness“ is being checked todetect potential faults, two diam-eters, one at right angles to theother can be taken and noted in

b

a

18,30 mm

20,00 mm


Fig. 10

the records. The entry into therecords might read „Rope diam-eter : 20.4/20.5mm“.

8.4 Measuring rope lay

After a rope has been fitted to theappliance, its length cannot bemeasured again accurately with-out a great deal of trouble. Thepurpose of measuring the lengthof lay is to detect any increase inthe rope length which may havebeen caused by corrosion, coredeterioration or rope rotation(unlaying). With a new rope the

wires and strands should be al-lowed to settle into their perma-nent position. Six or seven liftingcycles with a light to mediumload are recommended beforemeasuring the lay of the rope. Tominimise error, the measurementshould be made over four laysand the length divided by four tofind the average lay length.

On eight strand ropes the eight,sixteenth, twentyfourth andthirtysecond strands must bemarked. Using a straight lengthof the rope and with the rope un-der no load, first mark any strandon the crown with a piece of

chalk: this strandnow becomes “crownzero”. Excluding thisstrand, count thenext eight strandsand mark the eighthstrand with chalk.Exclude the eighthstrand and repeatthis procedure a fur-ther two times. Themeasured length be-tween the outerchalk marks is thendivided by four togive the lay length.

As a rough check onthe overall accuracyof the chalk mark-ing, the length of layfor eight strandropes is approxima-


The unskilled use of a screw-driver or Marlin Spike to examinethe rope core can cause seriousdamage to the rope.

8.6 Changes in ropestructure

In addition to the examinationareas detailed in section 4, defor-mation caused at any point in themain working area can movealong the rope. Waviness, and inparticular, a birdcage can bemoved along the rope by the ac-tion of the sheaves. A degree ofslackness in the outer cover of amulti- strand rope may not besufficient to form an immediatebirdcage. However, slackness canbe “squeezed” along the rope.With the normal length of ropeout any slackness in the outercover will usually be found at theend termination or where therope meets the drum.

8.7 Inspecting sheavesand drums

Remarks in this section are in-tended to apply equally tosheaves and drums.

A tight groove in a sheave ordrum will subject the rope toenormous radial pressure. Rapiddeterioration and premature wirefailure, particularly in the valleys

tely between 6.25 and 6.5 x thediameter of the rope e.g. using alay length of 6.5 x rope diameter,four lay lengths of a 32mm diam-eter rope will be 32mm x 6.5 x 4 =832mm.

An alternative method of meas-uring the rope lay is to secure thefree end of the roll of adding ma-chine paper to the rope with ad-hesive tape. The paper is rolledout over the rope and simultane-ously the wax pencil is drawnover the paper, providing a clearprint of the outer wires of therope. The finished print can befiled for comparison with latermeasurements.

A third method is to wrap typingcarbon papers round the ropeunder the roll of paper. By rub-bing along the paper with a pieceof cardboard, the carbon mark-ing on the underside of the papercan be confined to the tops of thestrand crowns.

8.5 Checking the stabilityof the rope

A rope in good condition will haveall strands tightly laid. A screw-driver inserted between strandswhen twisted, should meet withstiff resistance. If the screwdrivercan be twisted between differentpairs of strands without muchresistance, a full examinationshould be carried out.


A B C

A B

nom

inal

rope

dia

met

er +

6%

groove diameter

groove

dia

met

er =

C

max.

num

ber

of

cycl

es

[ –

] u

nti

l dis

card

optimum

Fig. 11

between strands, can be expected(Fig. 11, A).

On the other hand a wide groovewill not provide essential supportto a rope under load. Oval shapeddeformation is produced result-ing in uneven distribution of theload between individual wireswith consequent early failure(Fig. 11, C).

Sheaves can be checked withgauges which are available on theopen market. The use of speciallymade circular templates is pre-ferred.

The recommend size for a sheavegauge is the nominal rope diam-eter + 6% to +10% (Fig. 11, B). In

order to establish the size of asheave groove, templates for thesizes above and below the recom-mended size will be required.

The sides and tread of sheaveswhich have been in use for sometime are often heavily coated withold lubricant, some of which mayfirst have to be removed with ascraper. By inserting the tem-plate as far as possible and draw-ing it through the remaining lu-bricant, the fit of the template re-lative to the sheave tread can beassessed.

The correct template should be incontact with the sheave tread forabout 130°. If the template onlytouches the side flanges, the


groove is too tight. If the templatetouches only the bottom part ofthe tread, the groove is too wide.

Attention should also be given tothe flanges of the sheaves. Ab-sence of lubricant, scratching orunexpected wear on one side willindicate (a) misalignment of thesheave and (b) the danger oftorque being induced into therope due to the rope rolling downthe flange into the tread.

The tread should be cleaned andcarefully examined for any sign ofridging or imprinting. In the caseof imprinting with the rope profilethe rope in service may havecaused the damage and is un-likely to be seriously affected. A

Fig. 13Fig. 12

replacement rope will not fit ex-actly into the imprint and willsuffer serious damage during theearly part of its service.

When a rope change is made, thesheaves should be checked foreccentricity and the bearing forwear and free running.

9. Electro-magneticwire rope examination

After a period in service surfacewear and/or a number of wirebreaks will indicate the rope con-dition has deteriorated and dis-card may be imminent. Specificworking conditions however, may

Point ofcontact


lead to internal wire breaks andto internal loss of metallic area. Itmay be surprising to learn thatthis applies in particular to ropeswhich, for safety reasons, are op-erated with large diametersheaves and high factors ofsafety.

Dynamically loaded ropes orropes which are subjected totorque when working, can sufferfrom internal wire breaks causedby overstrained interior rope ele-ments. In addition, when the ree-ving system includes sheaveslined with plastic or all plasticsheaves, these sheaves offermore elastic support than steelsheaves. The pressure betweenouter wires and the sheavegrooves can be reduced to suchan extent that with some ropeconstructions the first wirebreaks will occur, not on the sur-face, but within the rope. In allthese cases electro- magnetic tes-ting will allow non-destructiveexamination and appraisal of therope’s internal condition.

Electro-magnetic testing equip-ment available on the market al-lows - depending on individualdesign - indication or continuousrecording of localised damagesuch as single broken wires,breaks of strands, soldered andwelded joints as well as wire pit-ting and even detection of re-duced metallic area caused bycorrosion and abrasion over thewhole rope length.

The data are plotted as a functionof the rope length, which is con-tinually measured either duringthe inspection or, if a recording isdone, during the following analy-sis. In this way every signal onthe recording can unmistakablybe related to a zone on the rope.This method allows a more pre-cise visual inspection of thosesections of the rope whichshowed exceptional inconsisten-cies during the electro-magneticinspection. Furthermore, record-ing the data during regular electro-magnetic inspections makesit possible to compare the resultswith previous recordings. In thisway the advance of the deteriora-tion of the rope can be ascer-tained.

Electro-magnetic testing equip-ment for wire ropes was alreadybeing developed at the beginningof the 20th century. Only very fewspecialists could use the equip-ment properly but over the pastfew years the use of these instru-ments has been greatly improvedso that they are now at the com-mand of a much wider range ofusers.

It is likely that within a few yearsthere will be equipment on offerwhich not only records measureddata but also - by means of a mi-cro computer - will process thedata with regard to amplitudeand frequency. In this way theequipment will provide the exam-iner with data such as frequency


Fig. 14

curves and the accurate assess-ment of the reduction in breakingstrength.

At the moment instruments arebeing developed which, apartfrom the data mentioned above,can also record the rope diameterand the lay length of the rope.This will enable them to registerout-of-roundness of the rope di-ameter, corkscrew-like deforma-tions or changes of the laylengths along the rope length.

For inspection a test head isclamped around the rope. Thenthe whole length of the rope ispulled through the test head. Ifthis is not possible, as in the caseof suspended ropes of rope ways,the test head is drawn along the

wire rope. During this procedureall test data are transmitted viacable or radio to an amplifier. Thetest data are indicated either op-tically or acoustically, recordedon magnetic tape or representedgraphically during the test. Anelectro-magnetic test instrumentis shown in Fig. 14.

Calibration of the testing equip-ment requires great care. A re-commended method of checkingthe function and accuracy of theequipment is to attach lengths ofwire, having diameters equal tothe largest and smallest sizes inthe rope, along the first metres ofrope length. By means of sello-tape these wires can be securedin the strand valleys. At the be-ginning of the recording strip


Fig. 15

a

b

chart the examiner will obtainreference data indicating the sizeof the amplitudes of the testwires.

Fig. 15a illustrates a typical dia-gram of a rope section with wirebreaks. Fig. 15b shows the recor-ding of a rope section affected bycorrosion.

Selecting the suitable test instru-ment, competent handling andthe correct interpretation of thedata require a lot of experienceand expert knowledge. Variousuniversities, test institutes aswell as commercial firms, renderelectro-magnetic inspection ofwire ropes as a service.

The discard numbers of wirebreaks specified in the Standardsrefer solely to external wirebreaks. Appraising the conditionof the wire rope with regard to in-ternal wire breaks is therefore leftto the inspector; he would be welladvised to discard a wire ropewhen the total number of exter-nal and internal wire breaks,added together, reaches the dis-card number of wire breaks spe-cified in the Standards.

Electro-magnetic tests can not,and must not, totally replace vi-sual inspections. Yet, they pro-vide valuable additional informa-tion on the conditions of wireropes and must be regarded as auseful addition to the visual in-spection.


machine: application:

left hand lay right hand lay

regular lay langs lay

ungalvanized galvanized

location

measured

no. of broken wires

on 10 x dabrasion corrosion diameter/

ø-reduction mm/%other

* * **

date/ signaturefinal evaluation

type of end fitting:

type of rope:

nominal diameter [mm]:

tensile strength [N/mm ]:

rope length [m]:

date of installation: working hours to date:

* description, e.g. no, little, etc.** comments, e.g. description of a rope deformation

eff. Ø of new rope

2

allowed no.:

®


®

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fill

num

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s

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the

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ety

grea

ter t

han

5:

dis

card

num

ber o

f wire

bre

aks

fact

or o

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less

than

5:

dis

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fill f

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fact

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aver

age

wei

ght f

acto

r0,653

0,748

0,710

0,608

0,661

0,688

0,660

0,730

0,755

0,650

0,755

0,660

0,655

0,627

0,663

0,566

0,477

0,684

0,90

0,86

0,91

0,92

0,87

0,86

0,89

0,85

0,85

0,89

0,85

0,90

0,90

0,90

0,85

0,90

0,94

0,86

0,77

0,79

0,84

0,87

0,86

0,84

0,86

0,84

0,84

0,86

0,84

0,88

0,90

0,82

0,83

0,86

0,85

0,84

245

280

358

319

327

344

303

311

307

303

307

119

145

319

180

126

96

140

4

4

4

10

10

12

10

10

10

10

10

3

3

10

5

5

5

7

8

8

22

20

20

24

20

20

20

20

20

6

6

20

10

10

10

14

112

126

126

152

208

260

152

208

205

152

205

56

72

152

126

126

96

140

* up to approx. 40 mm Ø, 1770 N/mm2

** up to approx. 40 mm Ø

Discard Number of Wire Breaksaccording to the criteria of BS 6570


Additional CASAR literature• Alle Urheber- und Leistungsschutzrechte

vorbehalten-

Kein

Verleih!K

eineunerlaubte

Vervielfältigungen,Aufführung,Sendung•AllCopyrightsinrecordperformance

srese

rved

-No

lend

ing!

Una

utho

rized

dupl

icat

ion,

leas

e,pu

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perfo

rman

ceand broadcast

®

Handling, Installationand Maintenance of

Steel Wire Ropes

®

Wire Rope End Connections

® ®

The rotation characteristicsof steel wire ropes

®

TECHNICALDOCUMENTATION

®

CASAR CD-ROM

The first CASAR CD-ROM is an interactive tool withthe intention to inform the user about wire ropes.It offers many detailed information referring to:

• technical features• end connections• handling

• installation• maintenance• inspection

The CD-ROM is available at no cost.For Macintosh and Windows.

Which rope for my crane?


The CASAR product line

® ®® ®

®

® ® ® ®

®®®®

® ® ® ®

®®®


3,474,535,63

7,048,45

10,16

11,9213,8315,89

18,1120,3522,64

25,5228,2431,15

34,2737,2840,73

43,9347,7151,69

55,8159,5763,77

72,2581,7592,15

102,26113,08125,50

137,56149,89163,53

176,94186,35200,99

217,76232,42249,75

266,76284,67302,93

322,77339,31360,57

34,144,555,4

69,283,199,9

117,3135,9156,3

178,1200,1222,6

250,9277,7306,3

337,0366,5400,5

431,9469,2508,3

548,8585,8627,1

710,5803,9906,1

1005,51111,91234,1

1352,71473,91608,1

1740,01832,51976,4

2141,32285,42455,9

2623,12799,32978,8

3173,93336,53545,6

1770 N/mm2 1960 N/mm2 1770 N/mm2 1960 N/mm2

(180 kp/mm2) (200 kp/mm2) (180 kp/mm2) (200 kp/mm2)

3,865,036,26

7,829,39

11,29

13,2515,3617,66

20,1222,6125,15

28,3531,3834,61

38,0841,4245,26

48,8153,0157,44

62,0166,1970,85

80,2890,84

102,39

113,62125,64139,44

152,85166,54181,70

196,61207,06223,32

241,95258,24277,50

296,40316,31336,59

358,64377,01400,64

37,849,361,3

76,692,1

110,7

129,8150,5173,0

197,2221,6246,5

277,8307,5339,2

373,2405,9443,5

478,3519,5562,9

607,7648,6694,4

786,7890,2

1003,4

1113,51231,31366,6

1497,91632,11780,7

1926,72029,22188,5

2371,12530,82719,5

2904,73099,83298,5

3514,63694,73926,2

7 25,0 22,5 44,2 4,51 49,0 4,998 32,8 29,5 58,1 5,92 64,3 6,569 40,8 36,7 72,2 7,37 80,0 8,16

10 51,7 46,5 91,5 9,33 101,3 10,3311 62,2 56,0 110,2 11,23 122,0 12,4412 73,9 66,5 130,9 13,34 144,9 14,78

13 86,9 78,2 153,7 15,68 170,2 17,3614 100,4 90,4 177,7 18,13 196,8 20,0715 116,0 104,4 205,3 20,94 227,4 23,19

16 132,3 119,0 234,1 23,87 259,3 26,4417 147,8 133,0 261,5 26,67 289,6 29,5318 165,5 149,0 293,0 29,88 324,4 33,08

19 186,6 167,9 330,3 33,68 365,7 37,3020 205,0 184,5 362,9 37,00 401,8 40,9821 226,7 204,0 401,2 40,91 444,3 45,30

22 250,0 225,0 442,5 45,12 490,0 49,9623 271,2 244,1 480,0 48,94 531,5 54,2024 296,0 266,4 523,8 53,42 580,1 59,15

25 319,9 287,9 566,2 57,74 627,0 63,9426 347,0 312,3 614,2 62,63 680,2 69,3627 372,9 335,6 660,0 67,30 730,9 74,53

28 402,1 361,9 711,7 72,57 788,1 80,3629 432,5 389,2 765,5 78,06 847,7 86,4430 464,7 418,3 822,6 83,88 910,9 92,89

32 526,4 473,7 931,7 95,00 1031,7 105,2034 591,2 532,1 1046,4 106,71 1158,8 118,1636 661,5 595,3 1170,8 119,39 1296,5 132,21

38 742,5 668,3 1314,2 134,01 1455,3 148,4040 818,1 736,3 1448,0 147,66 1603,5 163,5142 902,7 812,4 1597,8 162,93 1769,3 180,42

44 994,4 895,0 1760,1 179,48 1949,1 198,7546 1083,6 975,3 1918,0 195,58 2123,9 216,5848 1186,5 1067,8 2100,1 214,15 2325,5 237,14

50 1286,3 1157,7 2276,8 232,17 2521,2 257,0952 1391,7 1252,5 2463,3 251,18 2727,7 278,1554 1501,4 1351,2 2657,4 270,98 2942,7 300,07

56 1610,3 1449,3 2850,3 290,65 3156,3 321,8558 1727,4 1554,7 3057,5 311,78 3385,7 345,2560 1848,6 1663,7 3272,0 333,65 3623,3 369,47

62 1973,9 1776,5 3493,8 356,27 3868,8 394,5164 2103,3 1893,0 3722,8 379,62 4122,5 420,3766 2236,8 2013,1 3959,1 403,72 4384,1 447,06

68 2374,4 2137,0 4202,7 428,56 4653,9 474,5670 2516,2 2264,5 4453,6 454,14 4931,7 502,8972 2662,0 2395,8 4711,7 480,46 5217,5 532,04

mm mm2 kg/%m kN t kN t kN t kN t

®

Calculated aggregate breaking load

with tensile strength of wire

Minimum breaking load

Nominaldiameter

WeightMetallicarea


9,8611,9814,16

16,7319,3122,21

25,2028,3932,13

35,7039,6443,60

47,7651,9457,08

61,6766,5272,02

77,4783,0788,84

101,48114,44127,74

142,90157,90169,83

185,75202,65222,75

9,1411,1113,30

15,6018,3020,80

23,5026,3230,00

33,5036,9040,20

45,0048,1453,50

57,9062,7066,75

72,7077,0083,40

94,90106,60120,90

134,50149,10164,41

180,20197,40215,64

8,3310,1212,10

14,1416,5018,80

21,2923,9927,15

30,3033,4936,84

40,6043,8848,30

52,3056,6060,85

65,6070,1975,30

85,7496,69

109,10

121,50138,00147,97

162,80178,30194,30

97,4118,4139,9

165,4190,9219,5

249,1280,6317,5

352,8391,7430,9

472,0513,2564,1

609,4657,4711,7

765,6821,0877,9

1002,81130.91262,3

1412,21560,41667,4

1823,71989,72187,0

89,6108,8130,8

152,7179,1204,0

230,6257,9293,9

329,0362,2396,1

441,4471,8524,3

567,9614,9654,2

712,9754,6817,4

930,01045,01185,0

1319,01462,01611,2

1767,01935,02113,3

81,999,5

118,2

139,0161,7184,5

209,4235,9266,9

297,1329,3362,3

398,5431,5474,3

512,8555,0598,3

643,7690,2738,1

843,4950,8

1070,0

1191,01360,01455,0

1596,01748,01908,4

1770 N/mm2 1960 N/mm2 2160 N/mm2 1770 N/mm2 1960 N/mm2 2160 N/mm2

(180 kp/mm2) (200 kp/mm2) (220 kp/mm2) (180 kp/mm2) (200 kp/mm2) (220 kp/mm2)

mm mm2 kg/%m kN t kN t kN t kN t kN t kN t

10 56,9 49,0 100,8 10,28 111,6 11,38 123,0 12,5411 69,0 59,3 122,1 12,45 135,2 13,79 149,0 15,1912 82,0 70,5 145,1 14,79 160,7 16,38 177,0 18,05

13 95,4 82,1 168,9 17,22 187,0 19,07 206,1 21,0214 110,4 94,9 195,4 19,93 216,4 22,06 238,5 24,3215 126,8 109,1 224,5 22,89 248,6 25,35 274,0 27,94

16 146,2 125,7 258,8 26,39 286,6 29,22 315,8 32,2017 163,5 140,6 289,4 29,51 320,5 32,68 353,2 36,0218 186,2 160,1 329,5 33,60 364,9 37,21 402,1 41,01

19 205,6 176,8 363,8 37,10 402,9 41,08 444,0 45,2820 227,5 195,6 402,6 41,06 445,9 45,47 491,4 50,1121 249,1 214,2 440,9 44,96 488,3 49,79 538,1 54,87

22 276,0 237,3 488,5 49,81 540,9 55,16 596,1 60,7823 303,3 260,9 536,9 54,75 594,5 60,62 655,2 66,8124 327,1 281,3 578,9 59,03 641,1 65,37 706,5 72,04

25 357,6 307,6 633,0 64,55 701,0 71,48 772,5 78,7826 382,0 328,5 676,1 68,94 748,6 76,34 825,0 84,1327 410,5 353,0 726,5 74,08 804,5 82,03 886,6 90,41

28 447,3 384,6 791,7 80,73 876,6 89,39 966,1 98,5129 472,3 406,2 835,9 85,24 925,7 94,39 1020,1 104,0230 505,4 434,7 894,6 91,23 990,6 101,02 1091,7 111,33

32 582,7 501,1 1031,3 105,16 1142,0 116,45 1258,5 128,3334 655,9 564,0 1160,9 118,38 1285,5 131,08 1416,7 144,4636 735,7 632,7 1302,1 132,78 1441,9 147,03 1589,0 162,04

38 823,3 708,1 1457,3 148,60 1613,7 164,55 1778,4 181,3440 910,5 783,1 1611,7 164,34 1784,7 181,98 1966,8 200,5542 1004,2 863,6 1777,5 181,25 1968,3 200,71 2169,1 221,19

44 1098,4 944,6 1944,1 198,24 2152,8 219,53 2372,5 241,9346 1198,3 1030,6 2121,0 216,29 2348,7 239,50 2588,4 263,9448 1317,2 1132,7 2331,4 237,73 2581,6 263,25 2845,0 290,11

®

Minimum breaking loadCalculated aggregate breaking load

with tensile strength of wireNominaldiameter

Metallicarea Weight

Further diameters upon request.


mm mm2 kg/%m kN t kN t kN t kN t

1770 N/mm2 1960 N/mm2 1770 N/mm2 1960 N/mm2

(180 kp/mm2) (200 kp/mm2) (180 kp/mm2) (200 kp/mm2)

®

5,346,788,37

10,0012,0514,18

16,3418,7921,36

23,9027,0929,89

33,3636,6340,25

43,7147,8452,47

57,0360,5465,10

69,8375,2880,03

85,5091,4896,46

102,35107,62121,02

133,46147,85

1691,60

175,90191,27209,12

227,54245,80264,94

283,49296,21318,17

338,99361,39379,39

401,44423,92

52,366,482,0

98,0118,0138,9

160,1184,1209,3

234,2265,5292,9

327,0359,0394,5

428,3468,9514,2

558,8593,3638,0

684,3737,8784,3

837,9896,5945,3

1003,01054,71186,0

1307,91448,91583,7

1723,81874,52049,4

2229,92408,82596,5

2778,22902,93118,0

3322,13541,63718,0

3934,14154,4

47,260,074,0

88,5106,6125,5

144,6166,3189,0

211,5239,8264,5

295,3324,2356,2

386,8423,4464,3

504,7535,8576,2

618,0666,3708,3

756,7809,6853,7

905,8952,4

1071,1

1181,11308,51430,1

1556,71692,81850,7

2013,72175,32344,8

2508,92621,52815,8

3000,13198,33357,6

3552,73751,7

4,806,107,53

9,0010,8412,76

14,7116,9119,22

21,5124,3826,90

30,0332,9736,23

39,3443,0647,22

51,3254,4958,59

62,8567,7672,03

76,9582,3386,82

92,1296,86

108,92

120,11133,06145,44

158,31172,15188,21

204,78221,22238,45

255,14266,59286,35

305,10325,25341,45

361,29381,53

8 30,8 28,3 54,5 5,56 60,3 6,159 39,5 36,3 69,9 7,12 77,4 7,89

10 48,3 44,4 85,4 8,71 94,6 9,65

11 60,0 55,2 106,3 10,84 117,7 12,0012 69,9 64,3 123,7 12,62 137,0 13,9713 81,1 74,6 143,6 14,64 159,0 16,22

14 93,9 86,4 166,2 16,95 184,1 18,7715 109,4 100,7 193,7 19,75 214,5 21,8716 123,9 114,0 219,3 22,37 242,9 24,77

17 139,5 128,4 247,0 25,18 273,5 27,8918 156,1 143,7 276,4 28,18 306,0 31,2119 177,5 163,3 314,2 32,04 347,9 35,48

20 195,8 180,2 346,6 35,34 383,8 39,1421 217,3 199,9 384,6 39,22 425,9 43,4322 237,6 218,6 420,6 42,89 465,7 47,49

23 258,6 237,9 457,6 46,67 506,8 51,6824 280,3 257,9 496,1 50,59 549,4 56,0225 302,0 277,8 534,5 54,51 591,9 60,36

26 326,8 300,6 578,4 58,98 640,4 65,3127 353,2 324,9 625,1 63,75 692,2 70,5928 375,9 345,8 665,3 67,84 736,7 75,12

29 407,7 375,1 721,6 73,59 799,1 81,4830 435,8 400,9 771,4 78,66 854,2 87,1031 464,3 427,1 821,8 83,80 910,0 92,79

32 495,4 455,8 876,9 89,42 971,1 99,0233 526,4 484,3 931,7 95,01 1031,7 105,2134 556,8 512,3 985,5 100,50 1091,3 111,29

35 585,9 539,1 1037,1 105,76 1148,4 117,1136 626,5 576,4 1108,9 113,08 1227,9 125,2138 705,1 648,7 1248,0 127,26 1382,0 140,92

40 779,4 717,0 1379,5 140,67 1527,6 155,7742 859,3 790,6 1521,0 155,10 1684,3 171,7544 942,5 867,1 1668,2 170,11 1847,3 188,37

46 1031,5 949,0 1825,8 186,18 2021,8 206,1748 1123,1 1033,3 1987,9 202,71 2201,3 224,4750 1212,7 1115,7 2146,5 218,88 2376,9 242,38

52 1309,7 1204,9 2318,2 236,39 2567,0 261,7654 1410,5 1297,7 2496,7 254,59 2764,7 281,9256 1508,1 1387,4 2669,3 272,19 2955,9 301,41

58 1581,2 1454,7 2798,7 285,39 3099,1 316,0260 1707,4 1570,8 3022,1 308,17 3346,5 341,2562 1845,1 1697,5 3265,9 333,03 3616,4 368,77

64 1966,1 1808,8 3480,0 354,86 3853,5 392,9566 2090,9 1923,6 3700,9 377,38 4098,1 417,8968 2183,5 2008,8 3864,8 394,10 4279,6 436,40

70 2352,0 2163,8 4163,0 424,51 4609,9 470,0872 2488,3 2289,3 4404,3 449,12 4877,1 497,33

Metallicarea

Nominaldiameter

Weight

Calculated aggregate breaking load

with tensile strength of wire

Minimum breaking load


Acknowledgement

The authors and the publisher are pleased to acknowledge thevaluable help received from Mr. M. J. McEntee, C. Eng., F. I. Mech. E.,F. I. Plant E., H. M. Principal Specialist Inspector (Engineering).

Readers Comments

For reasons of space, this booklet can only deal with general aspectsof wire rope inspection and examination. However, the publisher andthe authors are always pleased to give their opinions on specificproblems.

For future editions of this booklet, the authors look forward to re-ceiving readers’ suggestions for improvements or general comments.

These should be addressed to:

Wire Rope TechnologyDipl.-Ing. Roland VerreetGrünenthaler Straße 40a52072 AachenGermanyTelephone + 49 241 - 17 31 47Fax + 49 241 - 1 29 82e-mail [email protected]

or

William LindsayWire Rope Consultancy10 Poplar DriveLenzie, Glasgow, G66 4DNUKTelephone 041-776 1696


The material presented in this publication has been prepared in accordance with recognizedengineering principles and is for general information only. This information should not be usedwithout first securing competent advice with respect to its suitability for any given application. Thepublication of the material contained herein is not intended as a representation or warranty of thepart of Casar Drahtseilwerk Saar GmbH or the authors that this information is suitable for anygeneral or particular use or of freedom from infringements of any patent or patents. Anyone makinguse of this information assumes all liability arising from such use.

Permission to reproduce or quote any portion of this book as editorial reference is hereby granted.When making such reproductions or quotations, the title and the author of this publication mustbe mentioned.

This brochure is published byCasar Drahtseilwerk Saar GmbH,

manufacturers of the famous

Setting, Layout and Production: PR GmbH Werbeagentur und Verlag,Grünenthaler Straße 40a, 52072 Aachen, Germany

© 1989/1998 Casar Drahtseilwerk Saar GmbH

®

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��

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Phone ++ 49-68 41/80 91-0Fax ++ 49-68 41/86 94

Sales Dept.Phone ++ 49-68 41/80 91-39/44Fax ++ 49-68 41/80 91-29

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