Metal ropes and twisted slings based on them are necessary and critical elements of transport and construction equipment, industrial equipment and lifting devices. Steel wire ropes with organic and metal cores are used throughout. Interstate standard 2688-80 defines the types of double lay products with an organic core and linear contact of steel wires.
Cables of a similar design, but with a metal central strand, are produced in accordance with GOST 7668–80.
Steel rope GOST 2688–80 consists of six wire strands, which are twisted into one concentric surface around an organic core.
Natural and artificial materials are used as an organic core, such as:
- sisal;
- hemp;
- cotton yarn;
- nylon threads;
- nylon;
- polyethylene.
The core material is impregnated with a lubricant, which protects it from rotting and increases the life of the product. GOST 15037–69 lubricants are mineral oils containing solid hydrocarbons and copper salts. The organic core provides the necessary elasticity and flexibility of steel cables.
Each LK-R metal strand consists of 19 round wires twisted into three layers. The outer layer contains wires of different diameters, which ensures a linear type of contact in the strands, uniformity and strength of the rope surface. Cables with LK-R strands have high wear resistance and performance.
A design feature is the direction of twisting of the rope elements. The direction of twisting of the wire in the strands can be left or right. The combination of directions of elements during laying determines the properties of the cable. Single-laid ropes are flexible, wear-resistant, but easily unwind under load. Non-unwinding structures are made using cross or combined laying methods.
Round wire for steel cables is made from carbon steel without coating or with a galvanized outer layer.
Product range with organic core and steel wire shell, defined by GOST 2688–80. Steel ropes are divided according to mechanical properties, purpose, type of wire material, laying method and direction, manufacturing accuracy and degree of balance.
Classification differences
Cables are divided into types according to their intended purpose:
- GL - cargo lifts, which are used for ascent, descent, and movement of people and cargo.
- G - cargo, they are used for transporting and securing cargo.
The following grades are distinguished based on their mechanical properties:
- 1 - quality is normal.
- VK - high quality.
- B - increased quality.
By type of wire used:
- without external covering;
- with a galvanized layer.
Depending on the density of zinc, the following types of galvanized wire are distinguished: Coolant, S, Zh. Cables made of wire coated with Coolant are suitable for use in particularly harsh conditions and aggressive environments. For standard operating conditions in air, wire ropes made from uncoated or coated Group C wire are suitable.
In the direction of twisting the wire:
- Left lay - designated by the letter L.
- Right lay - no designation.
By combination of wire and strand directions:
- Single-sided lay: with the same direction of wires and strands in the rope.
- Cross: with the opposite position of the wire and strands.
- Combined: when strands of the right and left twisting directions are used simultaneously when laying the cable.
By laying method:
- Non-unwinding - designated by the letter N.
- Unwinding - without symbol.
Based on manufacturing accuracy, designs are distinguished:
- increased accuracy - T;
- normal.
By balance:
- unstraightened;
- straightened - R.
The balance of a metal rope is determined by the fact whether straightening - straightening the strands - was used in the process of its production. This process removes tension from the cable so the product remains straight after twisting.
Symbol
All symbols specified in GOST, apply when marking ropes. The first digit of the marking is the cross-sectional diameter of the cable, then follows the designation of the type of purpose, quality mark, coating group, direction of lay, curl characteristic, indication of straightening, accuracy and designation of the marking group.
For example: Rope 28 - G - 1 - L - 1670 GOST 2688–80. The designation of untwisted unstraightened cables of right-hand lay, normal precision manufacturing and made of uncoated wire will be shorter due to the lack of letters and numbers of the symbol. Only the diameter, purpose, quality group, left lay direction and marking group are indicated.
Straightened, non-unwinding cables of improved quality and manufacturing precision, made from wire coated with coolant, will have the following marking: Rope 21 - GL - V - coolant - N - R - T - 1470 GOST 2688–80.
Marking groups, dimensions and weight
Last number in the rope designation - a marking group that indicates the strength characteristics of the rope. The higher the number, the stronger the cable and the greater the load it can withstand during operation.
According to GOST 2688–80, ropes are produced with a cross-sectional diameter from 3.6 to 56 mm with strength characteristics from 1370 to 1860 N/mm 2 (140-190 kgf/mm 2). The standard tables indicate the diameters of the ropes, all wire layers of strands, strength characteristics and the approximate weight of 1 thousand meters of cable. The weight of a steel rope GOST 2688–80 can be determined by multiplying the weight value of 1 thousand meters of cable taken from the table by the length of the rope and dividing the resulting value by 1000.
1 thousand meters of rope with a diameter of 12 mm weighs approximately 520 kg; with a diameter of 21 mm - 1630 kg. The weight of one meter of a product with a thickness of 37 mm will be approximately 5 kg, and one meter with a thickness of 56 mm will be 11.6 kg.
The information below on the classification of ropes is far from new, and we cannot add practically anything new. You can easily find similar materials on other resources, so why do we host it? Looking at the classification below, you will understand that there are a large number of types of rope and sometimes even a specialist can find it quite difficult to understand what Rope 12-GL-VK-L-O-N-1770 GOST 2688–80 is.
Working with the same ropes, it’s quite easy to decipher everything, but if the client wants to buy a non-standard rope? This is where “Where to watch?” comes in. Where to get? What does this letter in the name mean? We have previously published material about ropes, but did not describe the classification in detail, so we hope that this article will be useful to you.
Classification, technical requirements, test methods, rules for acceptance, transportation, and storage of steel ropes are set out in GOST 3241-91 “Steel ropes. Technical conditions".
Classification of steel ropes
1. According to the main design feature:
- single lay or spiral consist of wires twisted in a spiral into one or more concentric layers. Single lay ropes, twisted only from round wire, are called ordinary spiral ropes. Spiral ropes that have shaped wires in the outer layer are called ropes of a closed structure. Single lay ropes intended for subsequent laying are called strands.
- double lay consist of strands twisted into one or more concentric layers. Double lay ropes can be single-layer or multi-layer. Single-layer six-strand double lay ropes are widely used. Double lay ropes intended for subsequent laying are called strands.
- triple lay consist of strands twisted in a spiral into one concentric layer.
2. According to the cross-sectional shape of the strands:
- round
- fancy-spun(trihedral strand, flat strand), have a significantly larger surface area for contact with the pulley than round strand.
3. By type of laying of strands and single lay ropes:
- TK- with point contact of wires between layers,
- OK- with linear contact of wires between layers,
- LK-O- with a linear touch of the wires between the layers with the same diameter of the wires along the layers of the strand,
- LK-R- with linear contact of wires between layers with different diameters of wires in the outer layer of the strand,
- LK-Z- with linear contact of the wires between the layers of the strand and the filling wires,
- LK-RO- with linear contact of wires between layers and having in strands layers with wires of different diameters and layers with wires of the same diameter,
- TLC- with a combined point-linear contact of wires in strands.
Strands with point contact of wires are produced in several technological operations depending on the number of layers of wires. In this case, it is necessary to apply different wire laying steps for each layer of the strand and twist the next layer in the opposite direction to the previous one. As a result, the wires between the layers intersect. This arrangement of wires increases their wear during shear during operation, creates significant contact stresses that promote the development of fatigue cracks in the wires, and reduces the coefficient of filling of the rope section with metal.
Strands with linear contact of wires are produced in one technological step; At the same time, the consistency of the lay pitch is maintained, and the same direction of the lay of the wires for all layers of the strand, which, with the correct selection of wire diameters across the layers, results in a linear contact of the wires between the layers. As a result, the wear of the wires is significantly reduced and the performance of ropes with linear contact of the wires in the strands increases sharply in comparison with the performance of TK type ropes.
Strands of point-linear touch are used when it is necessary to replace the central wire in linear touch strands with a seven-wire strand, when a layer of wires of the same diameter with a point touch is laid on a single-layer seven-wire strand of the LK type. The strands may have increased anti-twist properties.
4. According to core material:
- OS- with an organic core - as a core in the center of the rope, and sometimes in the center of the strands, cores made of natural, synthetic and artificial materials are used - from hemp, manila, sisal, cotton yarn, polyethylene, polypropylene, nylon, lavsan, viscose, asbestos .
- MS- with a metal core - in most designs, a double lay rope of six seven wire strands located around a central seven wire strand is used as a core; in ropes in accordance with GOST 3066-80, 3067-88, 3068-88, a strand is used as an MS the same design as in the layer. It is advisable to use them when it is necessary to increase the structural strength of the rope, reduce the structural elongation of the rope during tension, and also at high temperatures of the environment in which the rope operates.
5. According to the laying method:
- Non-unwinding ropes - N- strands and wires retain a given position after removing the ties from the end of the rope or are easily laid by hand with slight untwisting, which is achieved by preliminary deformation of the wires and strands when twisting the wires into a strand and strands into a rope.
- Unwinding ropes- wires and strands are not pre-deformed or are insufficiently deformed before they are laid into strands and into a rope. Therefore, the strands in the rope and the wires in the strands do not retain their position after the ties are removed from the end of the rope.
6. By degree of balance:
- Straightened rope - R- does not lose its straightness (within the permissible deviation) in a freely suspended state or on a horizontal plane, because After laying the strands and spar, respectively, the stresses from deformation of the wires and strands are removed by straightening.
- Unstraightened rope- does not have this property, the free end of an unstraightened rope tends to form a ring due to the deformation stresses of the wires and strands obtained during the rope manufacturing process.
7. In the direction of the rope lay:
- Right lay- not indicated
- Left lay- L
The direction of lay of the rope is determined by: the direction of lay of the outer layer wires - for single lay ropes; direction of lay of the outer layer strands - for double lay ropes; direction of lay of the strands into the rope - for triple lay ropes
8. According to the combination of lay directions of the rope and its elements:
- Cross lay- the direction of lay of strands and strands is opposite to the direction of lay of the rope.
- Single-sided lay - O- the direction of laying the strands into a rope and the wires in the strands are the same.
- Combined lay- K with the simultaneous use of strands in the rope of the right and left directions of lay.
9. According to the degree of coolness
- Spinning- with the same direction of lay of all strands along the layers of the rope (six- and eight-strand ropes with an organic and metal core)
- Low-rotating- (MK) with the opposite direction of lay of rope elements in layers (multi-layer, multi-strand ropes and single lay ropes). In non-rotating ropes, due to the selection of laying directions of individual layers of wires (in spiral ropes) or strands (in multi-layer double lay ropes), rotation of the rope around its axis is eliminated when the load is freely suspended.
10. According to the mechanical properties of the wire
- Brand VK- High Quality
- Brand B- improved quality
- Brand 1- normal quality
11. According to the type of surface coating of the wires in the rope:
- Made from uncoated wires
- Made from galvanized wire depending on the surface density of zinc:
- group C- for medium aggressive working conditions
- group F- for harsh aggressive working conditions
- coolant group- particularly harsh aggressive working conditions
- P- rope or strands are coated with polymer materials
12. According to the purpose of the rope
- Cargo - GL- for lifting and transporting people and loads
- Freight - G- for lifting and transporting loads
13. According to manufacturing accuracy
- Normal accuracy- not indicated
- Increased accuracy - T- stricter maximum deviations for rope diameter
14. According to strength characteristics
Marking groups of temporary tensile strength N/mm2 (kgf/mm2) - 1370 (140), 1470 (150), 1570 (160), 1670 (170), 1770 (180), 1860 (190), 1960 (200), 2060 (210), 2160 (220)
Examples of symbols for steel ropes
- Rope 16.5 - G - I - N - R - T - 1960 GOST 2688 - 80 Rope with a diameter of 16.5 mm, cargo purpose, first grade, made of uncoated wire, right-hand cross lay, non-unwinding, straightened, high precision, marking group 1960 N/mm2 (200 kgf/mm2), according to GOST 2688 - 80
- Rope 12 - GL - VK - L - O - N - 1770 GOST 2688 - 80 Rope with a diameter of 12.0 mm, for cargo purposes, grade VK, made of uncoated wire, left one-sided lay, non-unwinding, unstraightened, normal accuracy, marking group 1770 N/mm2 (180 kgf/mm2), according to GOST 2688-80
- Rope 25.5 - G - VK - S - N - R - T - 1670 GOST 7668 - 80 Rope with a diameter of 25.5 mm, cargo purpose, grade VK, galvanized according to group C, right-hand cross lay, non-unwinding, straightened, increased accuracy , marking group 1670 N/mm2 (170 kgf/mm2), according to GOST 7668 - 80
- Rope 5.6 - G - V - Zh - N - MK - R - 1670 GOST 3063 - 80 Rope with a diameter of 5.6 mm, cargo purpose, grade B, galvanized according to group Zh, right lay, non-unwinding, low-twist, straightened, marking group 1670 N/mm2 (170 kgf/mm2), according to GOST 3063 - 80
Each rope design has advantages and disadvantages that must be properly taken into account when selecting ropes for specific operating conditions. When choosing, you should maintain the necessary relationships between the diameters of the winding elements and the diameters of the ropes and their outer wires, as well as the necessary safety margin to ensure trouble-free operation.
Single lay ropes made of round wires - ordinary spiral (GOST 3062-80; 3063-80; 3064-80) have increased rigidity, so they are recommended for use where tensile loads on the rope predominate (lightning protection cables of high-voltage power lines, fences, guy wires, etc.)
Double lay ropes with linear contact of wires in strands with ease of manufacture, they have relatively high performance and have a sufficient number of different designs. The latter allows you to select ropes for operation under large end loads, with significant abrasive wear, in various aggressive environments, with the minimum permissible ratio of the diameter of the winding member and the diameter of the rope.
Ropes type LK-R (GOST 2688-80, 14954-80) should be used when during operation the ropes are exposed to aggressive environments, intense alternating bending and work in the open air. The great structural strength of these ropes allows them to be used in many very stressful operating conditions of crane mechanisms.
Ropes type LK-O (GOST 3077-80, 3081-80; 3066-80; 3069-80; 3083-80) They work stably under conditions of severe abrasion due to the presence of wires of increased diameter in the upper layer. These ropes are widely used, but their normal operation requires a slightly increased diameter of blocks and drums.
Ropes type LK-Z (GOST 7665-80, 7667-80) used when flexibility is required, provided that the rope is not exposed to an aggressive environment. It is not recommended to use these ropes in aggressive environments due to the thin filling wires in the strands, which are easily corroded.
Ropes type LK-RO (GOST 7668-80, 7669-80, 16853-80) They are distinguished by a relatively large number of wires in the strands and therefore have increased flexibility. The presence of relatively thick wires in the outer layer of these ropes allows them to be successfully used in conditions of abrasive wear and aggressive environments. Due to this combination of properties, the LK-RO type construction rope is universal.
Double lay ropes with point-linear contact of wires in strands of type TLK - O (GOST 3079-80) should be used when the use of ropes by linear contact of the wires in the strands is impossible due to a violation of the minimum permissible installation ratios between the diameters of the winding elements and the diameters of the rope wires or when it is impossible to ensure the recommended safety factor.
Double lay ropes with point contact of wires in TK type strands (GOST 3067-88; 3068-88; 3070-88; 3071-88) Not recommended for critical and intensively operating installations. These ropes can only be used for non-stressful operating conditions, where alternating bends and pulsating loads are insignificant or absent (slings, bracing ropes, temporary timber fastenings, support and brake ropes, etc.)
Multi-strand double lay ropes (GOST 3088-80; 7681-80) Depending on the accepted directions of laying of the strands in individual layers, they are made ordinary and non-twisting. The latter ensure reliable and stable operation on mechanisms with free suspension of the load, and the large supporting surface and lower specific pressures on the external wires make it possible to achieve a relatively high performance of the rope. The disadvantages of multi-strand ropes are the complexity of manufacturing (especially pre-deformation), the tendency to delamination, and the difficulty of monitoring the condition of the internal layers of the strands.
Triple lay ropes (GOST 3089-80) used when the main operational requirements are maximum flexibility and elasticity of the rope, and its strength and supporting surface are not of decisive importance. Organic cores in strands are appropriate when the rope is intended for towing and mooring, where increased elastic properties of the rope are required. Due to the use of wires of small diameters compared to the wires of double lay ropes, triple lay ropes require pulleys of significantly smaller diameters for normal operation.
Three-strand ropes (GOST 3085-80) characterized by increased structural stability, a very high fill factor and a large supporting surface. The use of these ropes is especially suitable for high end loads and severe abrasive wear. It is recommended to use these ropes both in installations with friction pulleys and in multi-layer winding on drums. The disadvantages of triangular strand ropes are sharp bends of the wires on the edges of the strands, increased rigidity of the rope, and the complexity of manufacturing the strands.
Flat ropes (GOST 3091-80; 3092-80) are used as counterbalancers in mine hoisting installations. The advantages of these ropes include their non-twistability. However, the manual operations involved in sewing ropes and the relatively rapid destruction of the collar during operation limit the extent to which these ropes can be used in industry.
Classification of ropes according to domestic and foreign standards
| GOST | DIN | EN | B.S. | ISO |
| GOST 2688-80 | DIN 3059-72 | EN 12385 | BS 302 6x19 (12/6/1) FC | |
| GOST 3062-80 | DIN 3052-71 | |||
| GOST 3063-80 | DIN 3053-72 | |||
| GOST 3064-80 | DIN 3054-72 | |||
| GOST 3066-80 | DIN 3055-72 | EN 12385 | BS 302 6x7 (6/1)WSC | |
| GOST 3067-88 | DIN 3060-72 | EN 12385 | BS 302 6x19 (12/6/1)WSK | |
| GOST 3068-88 | DIN 3066-72 | |||
| GOST 3069-80 | DIN 3055-72 | EN 12385 | BS 302 6x7 (6/1) FC | |
| GOST 3070-88 | DIN 3060-72 | BS 302 6x19 (12/6/1) WSC | ||
| GOST 3071-88 | DIN 3066-72 | BS 302 6x37 (18/12/6/1) FC | ||
| GOST 3077-80 | DIN 3058-72 | EN 12385 | BS 302 6x19 (9/9/1) FC | ISO 2408 |
| GOST 3079-80 | ||||
| GOST 3081-80 | DIN 3058-72 | EN 12385 | BS 302 6x19 (9/9/1) WRC | ISO 2408 |
| GOST 7668-80 | DIN 3064-72 | EN 12385 | BS 302 6x36 (14/7&7/7/1) FC | ISO 2408 |
| GOST 7669-80 | DIN 3064-72 | EN 12385 | BS 302 6x36 (14/7&7/7/1) IWRC | ISO 2408 |
| GOST 14954-80 | DIN 3059-72 | EN 12385 | BS 302 6x19 (12/6+6F/1) IWRC |
Steel cable is recommended for wide use in various lifting devices, from manual hoists to cranes, for lifting and moving loads, parts and structural elements. Steel cable is part of most lifting mechanisms and devices. Depending on the design, steel cable has different flexibility and stretch coefficient. The steel cable is made of carbon steel and galvanized. Structurally, the steel cable is made of high-strength wire and core. The wire is wound around the core to form a strand; the strands, in turn, are also wound around the core to form a steel cable.
Example of steel cable designation: 6 x 7 + FC.
The first number is the number of strands of the cable.
The second is the number of wires in a strand.
The third is the number of cores, including the cores in the strands; if there is no number, there is one non-metallic one in the center of the steel cable, and a steel core in the strands.
Letters – core material: FC – vegetable, PVC – synthetic. If there is no letter designation, this means that the same strand as the side strands is used as the central core.
Technical characteristics of steel cable|
D, mm steel cable designation |
cross-sectional area, mm2 |
weight of one meter of steel cable, kg | ||
| 2 mm | 1,50 | 0,47 | 2,35 | 0,014 |
| 3 mm | 3,30 | 1,06 | 5,29 | 0,031 |
| 4 mm | 5,90 | 1,88 | 9,41 | 0,059 |
| 5 mm | 9,20 | 2,94 | 14,70 | 0,087 |
| 6 mm | 13,30 | 4,24 | 21,20 | 0,125 |
| 7 mm | 18,10 | 5,76 | 28,80 | 0,171 | 8 mm | 23,60 | 7,52 | 37,60 | 0,223 |
| 9 mm | 29,90 | 9,50 | 47,50 | 0,282 |
| 10 mm | 36,90 | 11,76 | 58,80 | 0,349 |
| 12 mm | 53,20 | 16,94 | 84,70 | 0,502 |
| 14 mm | 72,40 | 23,00 | 115,00 | 0,683 |
| 16 mm | 94,50 | 30,20 | 151,00 | 0,892 |
GOST 2688-80
Group B75
INTERSTATE STANDARD
DOUBLE LAY ROPE TYPE LK-R CONSTRUCTION 6x19(1+6+6/6)+1 o.s.
Assortment
Two lay rope type LK-R construction 6x19 (1+6+6/6)+1 o.c. Dimensions
MKS 77.140.65
OKP 12 5100, 12 5200
Date of introduction 1982-01-01
By Decree of the USSR State Committee on Standards dated April 23, 1980 N 1833, the introduction date was set at 01/01/82
The validity period was lifted by Gosstandart Decree dated November 22, 1991 N 1752
INSTEAD GOST 2688-69
Edition (May 2011) with Amendments No. 1, 2, approved in November 1986, November 1991 (IUS 2-87, 2-92)
1. This standard applies to double lay steel ropes with linear contact of wires in LK-R type strands with one organic core.
2. Ropes are divided according to characteristics
by purpose:
cargo-human - GL,
cargo - G;
by mechanical properties of grades: VK, V, 1;
by type of surface coating of the wires in the rope:
made of uncoated wire,
from galvanized wire depending on the surface density of zinc: S, F, OZH;
in the lay direction:
right,
left - L;
by combination of lay directions of rope elements:
cross,
one-sided - Oh,
combined - K;
by laying method:
non-unwinding - N,
unwinding;
by manufacturing accuracy:
normal,
increased - T;
by degree of balance:
straightened - R,
unstraightened.
Examples of symbols
Rope with a diameter of 12.0 mm, for cargo purposes, made of uncoated wire, grade B, left one-sided lay, non-unwinding, non-straightened, increased precision, marking group 1770 N/mm (180 kgf/mm):
Rope 12-GL-V-L-O-N-T-1770 GOST 2688-80
The same, with a diameter of 32.0 mm, for cargo purposes, grade I, galvanized according to the coolant group, right-hand cross lay, non-unwinding, non-straightened, normal accuracy, marking group 1370 N/mm (140 kgf/mm):
Rope 32-G-I-OZH-N-1370 GOST 2688-80
3. The diameter of the rope and its main parameters must correspond to those indicated in the table.
Diameter, mm | Estimated cross-sectional area of all wires, mm | Approximate weight of 1000 m of lubricated rope, kg | Marking group, |
|||||
wire | ||||||||
ka- | center- | first layer (inner) | second layer (outer) | Breaking force N, |
||||
6 | 36 wires | 36 wires | 36 wires | total of all wires in the rope | rope |
|||
Continuation
Continuation
Continuation
Continuation
Notes:
1. Ropes, the breaking force of which is given to the left of the bold line, are made from uncoated and galvanized wire. Ropes made of galvanized wire of the Zh and OZh groups with diameters of 51.0 and 56.0 mm, marking group 1370 N/mm (140 kgf/mm), 42.0-47.5 mm marking group 1470 N/mm (150 kgf/mm) , 30.5-47.5 mm marking group 1570 N/mm (160 kgf/mm), 30.5-39.5 mm marking group 1670 N/mm (170 kgf/mm), 21.0-33.5 mm marking group 1770 N/mm (180 kgf/mm), 11.0-16.5 mm marking group 1960 N/mm (200 kgf/mm) are manufactured by agreement between the manufacturer and the consumer.
Ropes, the breaking force of which is given to the right of the bold line, are made from uncoated wire. It is allowed, by agreement between the manufacturer and the consumer, to manufacture ropes from galvanized wire.
2. Rope diameters greater than 10 mm are rounded to whole numbers or to 0.5 mm.
2, 3. (Changed edition, Amendment No. 1, 2).
4. Technical requirements, acceptance rules, test methods, labeling, packaging, transportation and storage in accordance with GOST 3241-91.
Electronic document text
prepared by Kodeks JSC and verified against:
official publication
Steel ropes. Assortment: Sat.GOSTov. -
M.: Standartinform, 2011
Steel rope (cable) is a particularly strong wire lifting equipment. It combines the strength of reinforcement and the flexibility of wire, eliminating their disadvantages. Most often, steel ropes are used in construction as load-bearing structural elements. With their help, heavy and extra-heavy loads are transported; the products are used for ceilings of stadiums, sports fields and fastening bridges.
Ropes produced according to different GOST standards have a specific purpose, which is associated with different levels of strength:
Types of steel ropes
There are many types of steel ropes. To make it easier to navigate the assortment, they are classified depending on their characteristics.
Core material
The element itself is necessary to enhance wear resistance, increase the flexibility and strength of the product. The core extends the life of the entire rope and reduces the risk of deformation.
There are two options for cores: metal (MC) and organic materials (these can be either natural or synthetic fibers, they are designated OS).
The second type of core is made from hemp or polypropylene. It is additionally impregnated with anti-corrosion substances, as well as compounds that protect against rotting. The metal core enhances the load-carrying capacity and makes it possible to work in more difficult conditions, at very high temperatures.
Design
Depending on the number of weaves, there are the following ropes:
- Single (also called spiral). They are created from wire woven in a spiral in three layers.
- Double lays - made of weaving in several layers.
- Triple lay - when creating the equipment, double lay ropes were used.
Strand lay type
Depending on the area of contact of the wire, steel ropes are divided into the following types:
point touch
Designation: TK
linear touch
Type: LinearDesignation: OK
Designation: LK-O
same wire diameter steel rope
Designation: LK-R
Type: Linear contact of a wire, between the layers of which there are wires with different diameters and the same
Designation: LK-RO
Type: Point-line tangency
Designation: TLC
By laying method
According to the degree of balance
According to the mechanical properties of the wire
The manufacturer indicates the quality of the wire with the following designations:
- high - VK;
- elevated - B
- normal - denoted by one.
Wire Surface Coatings
The surface may not have a coating, which is not indicated separately. Or a zinc coating can be applied, which allows the ropes to be used in special conditions:
- Coolant - especially hard;
- F - hard;
- C - moderately aggressive;
Cross - the direction of the strands is opposite to the direction of the rope.
One-way (O) - the direction of the strands in the rope and the wires in the strands are the same.
Combined (K) - the presence of both right and left lay directions in the rope.
By purpose
Cargo (GL) - for transporting personnel.
Cargo (G) - for moving cargo objects.
Production and marking of steel rope
Industrial production of steel ropes is carried out on specialized equipment. The entire process is automated, so the weave density of the product is very high. There are several ways to produce products. One of the standard methods: circular crimping of wire strands to deform them.
How is steel rope made?
At the manufacturing plant, each product is created in accordance with GOST. A tag with the necessary markings is attached to the steel rope. It contains all the necessary information for the buyer:
- name of the manufacturing enterprise,
- rope number,
- symbol,
- length,
- weight in kg,
- date of manufacture.
Marking example:
12 GL V L O ZH N R T 1770 GOST 2688-80
Explanation:
12 - rope diameter
GL - cargo-human
B - wire grade
L - left lay
O - one-sided lay
Zh - galvanizing group Zh
N - non-unwinding
R - straightened
1770 - marking group
Steel rope packaging
GOST 11127-78 for steel ropes for sale and transportation requires packaging by winding the product on a drum. The ends are tightly attached to the structure. The drum neck must exceed 15 rope diameters, the drum side must protrude 2 rope diameters with a rope thickness of 25 millimeters. The outside end of the rope is wrapped with synthetic or natural materials. At the customer's request, heavy-duty ropes can be sheathed with boards with a maximum gap of no more than 50 millimeters. This can be wrapped in waterproof paper according to GOST 515-77.
Rejection of steel rope
After the product starts operating, steel ropes are inspected monthly for defects. Inspections are carried out by engineering and technical specialists at the enterprise.
The steel rope is rejected based on the following criteria:
- the presence of wire breaks at the end seals;
- places with a large concentration of wire breaks;
- external and internal wear, presence of corrosion changes;
- wire exiting the lock;
- strand breaks;
- reducing the diameter of the rope;
- crushing strands;
- presence of bends;
- deformation under the influence of temperatures or electrical discharge.
The presence of a critical number of damages and deformations of the steel rope indicates that it is defective, so the product can no longer be used.
Taking into account the main characteristics, you can select a suitable steel rope for specific work, for example:
- Products made from single-weave round wire are used for increased loads. They have high stiffness values, so these ropes are suitable for power lines and as load-protecting ropes.
- Double weaving of the rope provides the product with special strength. Therefore, it is preferred when there are strong end loads.
- LK-R steel rope is used for open-air work, for example for construction cranes or any other lifting equipment. Since temperature changes and various weather conditions, among other things, affect the wear of the material, it is optimally suited for such working conditions.
- LK-O steel ropes are highly resistant to wear and are used in aggressive environments. The outer layer of such a cable is made of large-diameter wire, which allows the cable to be used for a long time. LK-O is widely used in elevators, on large ships, in the mountains when organizing rope bridges.
