verope® rope academy
Appropriate handling of special wire ropes
Do you want to learn everything about the technology of our ropes and how to handle them correctly?
We crated a collection of informative Videos that explain all you have to know to ensure the high quality of your verope® special wire rope.
Technical facts about special wire ropes
➜ Tech-Info 01:
Composition of a special wire rope
Every part that makes our ropes special
By the design of a wire rope, one understands the formation principle according to which the elements of the wire rope (the wires and the strands) are arranged relative to each other. The designation of a fiber core is FC, for an independent steel wire rope core it is IWRC. As an example all round strand ropes of the 6×19 Warrington design with a fiber core have the construction 6 x [1-6-(6-6)] – FC.
➜ Tech-Info 02:
Fill factor of a strand
what the fill factor number means
The fill factor of a strand is defined as the ratio of the metallic cross section (or as simplified calculation the sum of the single wire cross sections) related to the area of the smallest circle enclosing the strand. The fill factor specifies the amount of space which the strand takes in the rope meaning the quantity of steel. The fill factors of the most common strands are between 0,70 and 0,82. This means, that the amount of steel in the strand is about 70% to 82%. The fill factors of strands can be considerably increased by compacting. Usually the fill factor of a strand increases with an increasing number of wires. A Seale 15 strand (1-7-7) for example has a fill factor of about 0,77 and a Seale 19 strand (1-9-9) has a fill factor of about 0,79.
➜ Tech-Info 03:
Lay type of wire ropes
right or left hand lay is important for handling and using the rope
A distinction is made between right hand and left hand lay strands. The lay direction is left hand, when (moving away from the beholder) the wires are rotated counterclockwise. The lay direction of a strand is right hand, when its wires (moving away from the beholder) are rotated clockwise. The lay direction of a strand is often given by small s for the left hand lay strand and by a small z for the right hand lay strand.
➜ Tech-Info 04:
Fill factor of wire rope
The fill factor of a strand increases with an increasing number of wires.
The fill factor of a wire rope is understood to be the quotient of the metal cross-section of the rope (according to the definition, simplified as the sum of the individual wire cross-sections) in relation to the cross-section of the smallest of the smallest enveloping circle of the rope. The fill factor indicates what proportion of the space occupied by the wires and strands in the rope are filled with steel. The fill factors of the most common ropes are approximately between 0.46 and 0.75. This means that the proportion of steel to steel content of the rope volume is about 46% to 75% of the rope volume. Wire ropes with steel cores have higher fill factors than ropes with fiber cores. For example, a 6 x 25 Filler – FE rope has a fill factor 0.50, a 6 x 25 Filler – IWRC rope has a fill factor of 0.58.
➜ Tech-Info 05.1:
Strand construction of wire ropes pt. 1
What is the strand structure of wire ropes
The main types of strand construction are the one, two and three layer standard strands, as well as the parallel lay strands of the Seale, Filler, Warrington and Warrington-Seale construction types.The two and three layer standard strands have crossovers between the wires of the different wire layers. Here, the wire layers are stranded in separate operations in the same direction (abbreviation N) with the same stranding angle but different lay lengths. The so-called parallel lay strands (Seale, Filler, Warrington, Warrington-Seale) avoid the crossovers and instead create line contacts of the wires by stranding all wire layers with different stranding angles but the same lay length.
➜ Tech-Info 05.2:
Lay type of wire ropes
right or left hand lay is important for handling and using the rope
The make of a strand is the law of formation according to which the wires are arranged relative to each other. For example, all strands of the Seale type have the structure 1 – n – n (with n = 3, 4, 5, 6, 7, 8, 9 …). Wire layers which are stranded together in parallel in the same operation are connected by a minus sign ” – ” in the designation according to EN 12385-3. The designation of a Seale 17 strand is thus 1 – 8 – 8, the designation of a Seale 19 strand is 1 – 9 – 9.
➜ Tech-Info 06:
Wire rope diameter
A distinction is made between the nominal rope diameter and the actual rope diameter.
The nominal wire rope diameter is an agreed theoretical value for the diameter of the smallest circle enclosing the outer strands.The effective rope diameter, also called actual rope diameter, is the diameter of the smallest circle enclosing all outer strands, as measured on the rope itself. The tolerance range for the effective rope diameter is specified in related national and international standards. According to EN 12385-4 it is between -0% and +5% (for nominal rope diameters ≥ 8mm)This means that the effective rope diameter upon delivery must neither be smaller, nor 5% bigger than the nominal rope diameter.The tolerance range is often higher for smaller ropes like 3mm to 7mm nominal diameter.In the Oil and Gas industry, which is firmly based on US regulations, a tolerance range from -1% to +4% is applied.The effective rope diameter changes depending on the load applied. Therefore the effective rope diameter should in critical cases be measured on a rope that is loaded with 5% of the calculated breaking strength.
➜ Tech-Info 07:
Rope end connections and rope ends
What are the types of rope end connections
For some rope applications, e.g. pendant ropes, the rope length is essential. The following terms are used to describe the points of reference that are important to determine the rope length precisely. Some typical examples are added. By using the terms we want to make sure, that missunderstandings can be avoided. Besides the points of reference, the force under which the length must be correct shall also be determined by you. Without any information about the force, it is automatically assumed, that the length shall be correct at F = 0 kN. More detailed information about rope end connectors can be found here.
➜ Tech-Info 08:
Effects of wire rope lubricants
What effects does wire rope lubricant have on the rope
The wire rope lubricant has two essential tasks: on the one hand, it should protect the rope against corrosion, on the other hand, it should reduce the coefficient of friction between the rope elements themselves and between the rope and the sheave or drum. Reducing the coefficient of friction reduces the required drive power and reduces wear on the rope, sheave, and drum. We distinguish between wax-based lubricants and oil-based lubricants. While wax-based lubricants allow better handling, oil-based lubricants have the advantage that a torn lubricating film can close again automatically under the effect of gravity.
➜ Tech-Info 09.1:
Rope property Breaking strength
The calculated breaking strength of a wire rope is defined as the metallic cross-section of a wire rope (as the sum of the individual cross-sections of all the wires that make up a wire rope) multiplied by the nominal strength of the wires in the rope. The minimum breaking load of the wire rope is the calculated breaking load of the rope multiplied by the strand factor. The actual or real breaking load of a wire rope is the breaking load found in a breaking test of this rope. For a new wire rope, an actual breaking load must always be achieved; if a wire rope is not flexible enough, it must be forced to bend around a sheave of a specified diameter. This reduces the bending fatigue strength of the rope. Which is as high or higher than the minimum breaking load. The breaking load of a wire rope can be increased by increasing the metal cross-section in the rope, for example, by using strands with higher fill factors, by compacting the strands, by hammering the rope. Breaking strength can also be increased by increasing the tensile strength of the individual wires or by increasing the strand factor. The latter can be achieved, for example, by improving the contact surfaces between the rope elements or by using a plastic insert.
➜ Tech-Info 09.2:
Rope property Bending fatigue strength
What is the bending fatigue strength?
The bending fatigue strength of a wire rope is defined as the number of bending cycles a rope can achieve in fatigue bending test under specified conditions (for example, running over sheaves with a defined diameter and a specified line pull in relation to the rope’s minimum breaking load). The fatigue bending strength of a rope is increased by increasing the D/d ratio (= sheave diameter D: nominal rope diameter d) and by reducing the strand load. The bending fatigue strength of a wire rope can be increased by enlarging the contact area between the wire rope and the sheave and by enlarging the contact areas between the rope elements, for example by a plastic insert between IWRC and the outer strands. Due to the larger contact area between rope and sheave and greater flexibility, 8-strand wire ropes have a higher bending fatigue strength than 6-strand wire ropes of comparable make.
➜ Tech-Info 09.3:
Rope property flexibility
What influences the flexibility of a rope
A wire rope is usually more flexible the more strands and wires it has. However, flexibility is also affected by the lay lengths of the strands, the core rope, and the rope, as well as by the blocking (spacing) between the wires and between the strands. If a wire rope is not flexible enough, it must be forced to bend around a sheave of a specified diameter. This reduces the bending fatigue strength of the rope.
➜ Tech-Info 09.4:
Efficiency of the rope
When running over a sheave, the wire rope must be transferred from the straight to the bent state at the run-up point and from the bent to the straight state at the run-down point. The bearing of the sheave must also be rotated. Here, the frictional forces in the rope and the bearing must be overcome. This leads to a change in the rope force. The ratio of the rope forces on both sides of the sheave is called the rope efficiency, taking into account that this numerical value also includes the friction losses of the bearing. When measuring rope efficiency, the loss of line pull when running over sheaves is measured. Generally, an efficiency of 0.98 is assumed for wire ropes, i.e. a force loss of 2% per sheave.
➜ Tech-Info 09.5:
Rope characteristics wear resistance
Changes in line pull will cause changes in the rope length. Rope sections lying on a sheave or on the first wraps of a drum can only adapt to the changing line pull by sliding over the groove surface of the sheave or the drum when the length change occurs.
This relative motion will cause abrasion (both in the grooves and on the special wire rope). Using less and therefore larger outer wires can increase the wear resistance of the rope. The pressure between the sheave and the rope can be minimized due to optimized contact areas; therefore also the wear of the rope can be minimized. The wear resistance can also be influenced by the metallurgy of the outer strands.
The correct handling of special wire ropes
➜ Lesson 01:
Correct transport of rope reels
Transporting and unloading wire ropes with care
Learn how to transport and store verope special wire ropes correctly.
The handling of wire rope reels requires a certain degree of caution. The reel should therefore be unloaded from the loading area either by means of a fork lift, where the reel is lifted by means of a sufficiently dimensioned shaft as attachment points for the forks, or by means of an overhead crane as described in the picture below. The wound reel of wire rope should be moved as described before. Reels can easily be knocked over by the forklift which may damage both the reel and wire rope, so it is not advisable to do so.
➜ Lesson 02:
Correct measurement of rope sheave groove profiles
How to correctly determine the rope sheave groove profile.
Learn how to correctly determine the diameter of the sheave profile.
➜ Lesson 03:
Correct measurement of rope diameter
How to correctly determine the diameter of a verope special wire rope.
Learn how to correctly determine the rope diameter of a verope special wire rope.
To determine the exact rope diameter, a measuring device designed for this purpose must be used. The measurement must always be made over the crests (outer envelope circle of the rope). Measuring in the strand valleys falsifies the result considerably. In the case of ropes with an uneven number of outer strands, care must be taken to ensure that the measuring surfaces extend over several strands.
➜ Lesson 04:
Correct storage of rope reels
The ideal storage of rope spools in dry conditions.
Learn how to properly store verope rope spools.
Wire ropes must be protected from dirt and moisture during storage. Ideally, this is done in suitable sheds. When stored, round reels must be secured against rolling away. When stored outdoors, the ropes must be protected as best as possible from moisture and other environmental influences. Please ensure that the rope reel cover is selected in such a way that the rope underneath is always sufficiently ventilated to prevent corrosion due to condensation. Please also do not place the rope reels directly on the floor, but better on a pallet or squared timber. Bare wire ropes should not be stored outdoors for long periods. In unfavorable storage conditions, e.g. high temperatures, it may be necessary to relubricate the ropes before use.
➜ Lesson 05:
Handling ropes during unwinding and rewinding
How to handle ropes correctly during unwinding and rewinding
Rope installation must always be carried out by experienced, instructed personnel. The following points must be observed: For ropes supplied on rings, rope spools must be mounted on suitable unwinding devices, e.g. turntables or winding stands. Under no circumstances should the rope be pulled out of the ring or drum. This will introduce twists into the rope! In some rope configurations, the new rope is pulled in with the help of the old rope, etc. You can find many more hints here.
➜ Lesson 06:
Proper handling of specialty wire ropes
Learn how to properly handle specialty wire rope.
General handling procedures on how to remove or not remove the rope from the reel are shown in the following video.
➜ Lesson 07:
The correct cutting of special wire ropes
How to cut a special wire rope correctly
Steel wire ropes consist of many strands closed in a helix and due to this structure ropes must be secured against untwisting. This is usually ensured by welding the ends together or by attaching a suitable end con-nection. If the rope is to be shortened from its original length, the rope must be secured on both sides of the desired cutting point. The pictures below show the use of seizing wire, which must be applied in order to secure. The length of the joint is defined as follows: L = 2 x rope diameter d
➜ Lesson 08:
Relubrication of special wire ropes
Frequency and amount of relubrication
In general, we recommend relubricating the rope 10 times over its entire service life. In applications with a comparably short service life (e.g. due to high and rapid wear), relubrication must be carried out as required. The amount of relubricant to be applied can be defined by the following equation:
(rope weight m/g x rope length m) / 100 = lubricant quantity kg
➜ Lesson 09:
Methods and application of the relubricant
Learn how to handle special wire ropes properly
Generally, wire ropes are intensively lubricated during production. However, this lubrication must be renewed several times during the rope’s service life. Regular relubrication significantly increases the rope service life. As a general rule, care must be taken to ensure that the relubricant is compatible with the basic lubrication. It is recommended to follow the maintenance instructions of ISO 4309.
➜ Lesson 10:
The right rope inspection
Why rope inspection?
Ropes in rope drives are open gears that are exposed to external influences, but also have common signs of wear. Most importantly, ropes have a limited service life. When the rope reaches discard maturity, it has also reached the end of its service life. Rope discard maturity must be detected in time to avoid accidents such as rope breakage. This detection requires regular rope inspections that document to what percentage the rope used is already ready for discard.
➜ Lesson 11:
General visual inspection and daily visual inspection
Visual inspection and tools required for rope inspection.
A general visual inspection, which is to be carried out by the crane operator, is intended to detect obvious damage such as broken strands or faults in the reeving at an early stage and, if possible, to rectify them before operation is started. Areas near the end connection and rope zones that could come into contact with the crane structure and the rope drum should be inspected with increased attention. To be performed by visual inspection by the crane operator.
➜ Lesson 12:
How to measure the lay length of a rope.
Learn to measure lengths correctly
Whether a rope has been forcibly twisted or has generally undergone unnatural twisting can be determined by the lay length. To measure the lay length, you need the following utensils: paper strip (cash register roll), wax crayon, ruler, ballpoint pen. With the help of the paper strip and the wax crayon, a negative of the rope surface is created. For this purpose, a negative print of the rope surface is made by placing the paper and tracing over it with chalk. The result is an impression of the strands on the paper. To determine the lay length of the rope, a certain number of impressions must be counted. The number of outer strands is decisive here (in the picture below, there are therefore 8 outer strands). The distance between the start and end points gives the lay length in mm. It is recommended to count at least three measurements and divide the total length by three. This reduces measurement errors.
➜ Lesson 13:
Measuring rope sheave profiles
Learn to measure profiles with the right tools
A rope inspection involves not only examining the rope itself, but also the sheaves in which the rope runs. Special measuring tools are required to measure the groove diameters: various groove gauges and a flashlight.
Such groove gauges are available from verope® on request. The values indicated on the gauge are actual values and not nominal values, as is sometimes the case. The flashlight is used as an aid to determine the exact dimension. Here, the gauge in the groove is illuminated from behind. A visible light slit shows that the gauge used is too large or too small. If no light slit can be seen on the complete radius of the gauge, the correct groove dimension has been determined.
➜ Lesson 14:
Removal of protruding wires
Learn how to remove protruding wires
Ordinary lay ropes are less suitable for multi-layer drum spooling because the wires of the neighboring ropes can rub with each other. This leads to high mechanical wear.
The touch of the neighboring ropes during the spooling process is also well “audible”. This results in premature wire breaks. Lang’s lay ropes have proven themselves in multi-layer spooling because neighboring ropes can not rub into each other, which raises the lifetime of the rope significantly.