Steel cable 14 mm breaking load. Types of steel ropes, production, marking, rejection. Advantages of galvanized ropes

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 a linear touch of steel wires.

Cables of a similar design, but with a metal central strand, are produced according to GOST 7668–80.

Steel rope GOST 2688–80 consists of six wire strands, which are twisted into one concentric surface around the organic core.

Natural and artificial materials are used as an organic core, such as:

sisal;
hemp;
cotton yarn;
kapron threads;
nylon;
polyethylene.

The core material is impregnated with a lubricant that protects it from decay and increases the life of the product. Lubricants GOST 15037–69 are mineral oils containing solid hydrocarbons and copper salts. The organic core provides the necessary resilience and flexibility to steel cables.

Each metal strand LK-R consists of 19 round wires twisted in 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 strands LK-R 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 the directions of the elements during laying determines the properties of the cable. One-sided lay ropes are flexible, wear-resistant, but easily unwind under load. Non-twisting structures are made using the cross lay or combined lay methods.

Round wire for steel cables is made of uncoated carbon steel or with a galvanized outer layer.

Product range with organic core and steel wire shell, defines GOST 2688–80. Steel ropes are subdivided according to mechanical properties, purpose, type of wire material, lay method and direction, manufacturing accuracy and degree of balance.

Classification differences

Cables according to their purpose are divided into types:

GL - cargo people, which are used when lifting, lowering, moving people and goods.
G - cargo, they are used for transportation and fastening of goods.

According to mechanical properties, grades are distinguished:

1 - the quality is normal.
VK - high quality.
B - high quality.

Type of wire used:

without external coating;
with galvanized layer.

Depending on the density of zinc, the following types of galvanized wire are distinguished: OZH, S, ZH. Ropes made of wire coated with OZH are suitable for use in particularly harsh conditions and aggressive environments. For standard air service, uncoated or group C coated wire ropes are suitable.

In the direction of twisting the wire:

Left lay - denoted by the letter L.
Right lay - no designation.

According to the combination of wire and strand directions:

One-sided lay: with the same direction of the wires and strands in the rope.
Cross: with the opposite position of the wire and strands.
Combined: when strands of the right and left directions of twisting are used simultaneously when laying the cable.

By twisting method:

Non-twisting - denoted by the letter H.
Unwinding - without a symbol.

According to the accuracy of manufacturing, designs are distinguished:

increased accuracy - T;
normal.

For balance:

not straightened;
straightened - R.

The balance of a metal rope is determined by the fact whether straightening was used in the process of its production - straightening of the strands. This process takes stress off the cable so the product stays straight after twisting.

Symbol

Everything conventions specified in GOST, apply when marking ropes. The first digit of the marking is the diameter of the cable section, followed by the designation of the type of purpose, quality grade, coating group, lay direction, twisting characteristic, straightening, accuracy and marking group designation.

For example: Rope 28 - G - 1 - L - 1670 GOST 2688–80. The designation of untwisted unfastened cables of the right lay, of normal manufacturing accuracy and 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-twisting cables of increased quality and manufacturing accuracy, made of wire coated with coolant, will have the following marking: Rope 21 - GL - V - OZH - N - R - T - 1470 GOST 2688–80.

Marking groups, dimensions and weight

Last number in the designation of the rope - a marking group that indicates the strength characteristics of the rope. The larger the number, the stronger the cable and the greater the load that it can withstand during operation.

According to GOST 2688–80, ropes with a cross-sectional diameter of 3.6 to 56 mm are produced with strength characteristics from 1370 to 1860 N / mm 2 (140-190 kgf / mm 2). The tables of the standard indicate the diameters of the ropes, all wire layers of the strands, strength characteristics and the approximate weight of 1 thousand meters of the rope. The weight of a steel rope GOST 2688–80 can be determined by multiplying the weight value of 1 thousand meters of the 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 - 11.6 kg.

Steel ropes have found application in various industries and construction. Oil refining, coal mining, construction of industrial facilities and residential buildings, operation of marine and river vessels- this is not a complete list of the use of metal cables.

Scope of application

The main purpose of a steel rope is to carry out rigging, towing and lifting operations. High strength combined with flexibility make it possible to use metal products of this category for equipping lifting equipment and heavy equipment. This includes drilling equipment, cranes, excavators. In addition, steel wire ropes are used in the production of lifting and lowering mechanisms for passenger-and-freight elevators.

Linear touch wire ropes are used to create:

lifting installations in metalworking shops;
mine lifting equipment;
drilling rigs and mining machines;
earthmoving and road equipment;
suspended roads.

Ship cranes and truck cranes, telphers, winches and scrapers, elevators, drum winches and hydraulic lifts are equipped with steel cables.

The valuable properties of a metal cable include its flexibility and the ability to manufacture lifting devices that can withstand severe mechanical loads. Steel cables and additional elements in combination with which they are used are subject to strict requirements for compliance with state standards.

Excellent mechanical characteristics and corrosion resistance make it possible to use in the construction of critical structures - bridges, flyovers. Concrete structures reinforced with a metal cord acquire necessary strength, the ability to work out large dynamic and static loads.

The main parameters for choosing ropes are flexibility, strength, load capacity, as well as the limit values of their tension. To increase the resistance of metal products to aggressive environments, they can be subjected to additional processing. The scope of the rope depends on the material of manufacture, purpose and brand.

Description

Steel rope GOST 2688-80is a metal product that consists of an organic core and twisted steel wires. The core is the basis of the design and gives the product flexibility. It acts as a shock absorber, resists radial pressure when the rope is loaded and prevents its transverse deformation.

It can be made from:

polypropylene, polyethylene;
hemp or cotton fiber;
viscose, nylon, lavsan;
cord, sisal.

To protect the core from premature destruction and decay, it is impregnated with special anti-corrosion compounds that do not contain acids and alkalis. Rope lubricants are used to impregnate the core:

Torsiol-55;
Elascon;
BOZ-1;
SK-50;
KS-U.

During operation, when the rope is bent, the lubricant penetrates into the gaps between the wires, ensuring their uniform lubrication and protecting the metal from corrosion. Rope lubrication ensures long-term preservation of the core, reduces friction and wear of the inner and outer wires when the rope is working on blocks. The grease retains its qualities in a wide range of operating temperatures from -50 C to +50 C. Protective grease is used both in the manufacture of products and during operation. The composition is applied in a continuous layer with a thickness of at least 0.2 mm.

The double lay metal rope consists of six strands, which are made from wires of different diameters in the outer layer of the strands. Structural diagram of the rope 6×19 (1+6+6/6)+1 o.c. This design minimizes the risk of rupture and deformation of the product.

Ropes with a linear contact with wires of the LK-R type have a high working capacity, which allows them to be used for work in difficult conditions. Products in this category are resistant to abrasive wear and high end loads. Thanks to a wide range of standard sizes, you can choose a product with optimal technicalcharacteristics.

Specifications

Steel ropes manufactured in accordance with the standards of GOST 2668-80 have a section diameter from 3.6 mm to 56.0 mm. Products are classified according to several criteria. Ropes of increased manufacturing accuracy are indicated by the T index. Depending on the purpose, they are:

GL - cargo people, intended for installation on elevators;
G - cargo, which are used for the installation of all other mechanisms.

Steel cables are made with the right (R) and left lay, which is indicated by the index L. The direction of the lay is:

K - combined;
O - unilateral;
cross.

According to the method of laying the strands, the ropes are divided into:

H - non-twisting;
MK - low-rotation;
unwinding.

The use of ropes with a combined and cross lay reduces the torsion of the suspended load. The same direction of laying the wires creates a greater degree of twist. The opposite direction of the twisted strands gives the effect of low torsion (MK). Products marked H have a number of advantages in comparison with other types:

during operation they do not form loops and knots;
free ends do not untwist and do not bloom;
the cable does not make circular rotations when cutting, removing dressings.

Depending on the degree of balance, the ropes are straightened (P) and not straightened. As a result of straightening, the stress from the deformation of the wires and strands disappears. The product retains its straightness both on a horizontal plane and in a free suspended state.

According to mechanical properties, products are divided into grades:

B - ordinary quality;
VK - high quality;
1 - normal quality.

The material for the manufacture is steel wire with and without zinc coating. The surface density of zinc depends on the diameter of the wire.

Products with the letter designation C are used in aggressive conditions. The density of zinc is 20-110 g/m2.
Ropes marked with the letter Zh have a coating density of 25-150 g/m2 and are used in harsh conditions.
Products with the coolant marking are designed for operation in particularly harsh conditions with a high level of wear. The surface density of zinc varies from 60 to 245 g/m2.

Conventions

Product labeling contains complete information about the type and brand of products. An example of a symbol is a rope 14-G-VK-L-K-MK-T-1860 GOST 2688-80. Decryption:

14 - rope diameter;
G - cargo;
VK - high quality;
L - with the left lay direction;
MK - low-rotation;
T - increased accuracy;
1860 - marking group.

Rope production features

Galvanized wire ropes have increased stability to corrosion and are used in the following areas:

in the timber rafting and woodworking industry;
transport construction and shipbuilding, aircraft industry;
in metallurgy and mining industry;
production of construction equipment;
in the creation of production lines.

Priceproduct depends on its diameter, type and grade of steel used. The material for the manufacture of metal cables is low-alloy steel rope wire. It has a round section and is made of special wire rod of PK, VK, KK classes, which ensures high plasticity of the finished product. According to the type of surface, the rope wire is divided into:

light, without zinc coating with a diameter of 0.2 to 4.6 mm;
galvanized, with a diameter of 0.18-4.5 mm.

Structural and spring steel grades 45-85 are used as raw materials for the manufacture of wire. The choice of steel grade depends on the purpose of the final product. Reinforcing ropes are made of steel 70, 75, 80, 85. For aviation ropes, wire is made of steel grades 50.55, 60, 65.

It is possible to use corrosion-resistant steel grades5X17H12Mo2, 17X12H7, 5X17H12M2.Steel alloyed with silicon, manganese, chromium, nickel and molybdenum shows good anti-corrosion properties and is resistant to atmospheric moisture.

Quality control

Steel ropes used in production require regular monitoring of their condition. The detected defects are checked against the norms of rejection of products of this category. Marriage includes:

reconfiguration and destruction of the core;
extrusion of wires from strands;
wear of the outer layer of wires;
breakage of wires;
rope kink.

If such defects are found, the product is rejected.

Rope diameter measurement

The diameter of the rope is determined by measuring the actual size of the product using a caliper. Measurements are carried out in two sections, the distance between which is at least 1 m. In each section, the diameter is measured in two planes. The arithmetic mean of the four measurements must be within the tolerance limits specified for the nominal diameter.

Rope packaging

Buythe product can be in coils wound on wooden or metal coils. The length of the rope in the coil depends on its diameter and is 200, 500 and 1000 m. When placing an order, the required length of the rope is indicated in the contract concluded withmanufacturer.

The maximum deviation in length should not exceed 5% for ropes with a length of less than 400 m. For products with a length of more than 400 m, the permissible deviation is 20 m for every 1000 m.

internal diameter not less than 15 product diameters;
outer diameter not more than 1.2 m;
height not more than 0.8 m.

It is allowed to wind several lengths of rope of the same standard size onto a spool. In this case, the ends are firmly fixed, the outer end is bound and fixed on the inside of the cheek of the coil. For strapping are used: strands, ropes, ribbons, wire, organic core.

At the request of the customer, the GL ropes are wrapped with a polymer film or waterproof paper, the coils are sheathed with boards. The bays are firmly tied with soft wire or strands of rope at four or six points, while the attachment points should be evenly spaced around the circumference of the bay. Packaging of products that are shipped to the northern regions or sent by sea is carried out in accordance with GOST 15846-79.

Each cable is supplied with a certificate and a tag attached to the spool or coil. It indicates the serial number of the product, symbols, length and weight parameters.

rope weight

Steel ropes are elements lifting mechanisms and fixtures. For effective use equipment requires accurate information about the parameters of the rope - specifications, diameter,mass, how many meters in a ton. Weight 1 meterproduct depends on its diameter, which consists of the diameters of the wires - the central, inner and outer layers.

Rope diameter, mm	Weight of running meter, kg	Weight of 1000 m of lubricated rope, kg	Number of meters per ton
3,6	0,049	48,8	20408,2
3,8	0,055	55,1	18181,8
4,1	0,064	64,1	15625,0
4,5	0,074	73,9	13513,5
4,8	0,084	84,4	11904,8
5,1	0,096	95,5	10416,7
5,6	0,117	116,5	8547,0
6,2	0,142	141,6	7042,3
6,9	0,177	176,6	5649,7
7,6	0,211	211,0	4739,3
8,3	0,256	256,0	3906,3
9,1	0,305	305,0	3278,7
9,6	0,359	358,6	2785,5
11,0	0,462	461,6	2164,5
12,0	0,527	527,0	1897,5
13,0	0,597	596,6	1675,0
14,0	0,728	728,0	1373,6
15,0	0,844	844,0	1184,8
16,5	1, 025	1025,0	975,6
18,0	1,220	1220,0	819,7
19,5	1,405	1405,0	711,7
21,0	1,635	1635,0	611,6
22,5	1,850	1850,1	540,5
24,0	2,110	2110,0	473,9
25,5	2,390	2390,0	418,4
27,0	2,685	2685,0	372,4
28,0	2,910	2910,0	343,6
30,5	3,490	3490,0	286,5
32,0	3,845	3845,0	260,0
33,5	4,220	4220,0	237,0
37,0	5,015	5015,0	199,4
39,5	5,740	5740,0	174,2
42,0	6,535	6535,0	153,0
44,5	7,385	7385,0	135,4
47,5	8,430	8430,0	118,6
51,0	9,545	9545,0	104,8
56,0	11,650	11650,0	85,8

GOST 2688-80

Group B75

INTERSTATE STANDARD

DOUBLE TWAY ROPE TYPE LK-R DESIGN 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

ISS 77.140.65
OKP 12 5100, 12 5200

Introduction date 1982-01-01

By the Decree of the State Committee of the USSR for Standards of April 23, 1980 N 1833, the date of introduction was set to 01.01.82

The validity period was removed by the Decree of the State Standard of November 22, 1991 N 1752

INSTEAD OF 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 a linear touch of the wires in strands of the LK-R type with one organic core.

2. Ropes are subdivided according to features

by appointment:

cargo people - GL,

cargo - G;

according to the mechanical properties of grades: VK, V, 1;

according to the type of surface coating of the wires in the rope:

uncoated wire,

from galvanized wire, depending on the surface density of zinc: C, W, OZH;

in lay direction:

right,

left - L;

by combination of lay directions of rope elements:

cross,

one-sided - Oh,

combined - K;

by twisting method:

non-spinning - N,

unwinding;

manufacturing accuracy:

normal,

increased - T;

according to the degree of balance:

straightened - P,

not straightened.

Legend Examples

Rope with a diameter of 12.0 mm, for cargo use, made of uncoated wire, grade B, left-hand one-sided lay, non-twisting, non-straightened, increased accuracy, 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-twisting, non-straightened, normal accuracy, marking group 1370 N/mm (140 kgf/mm):

Rope 32-G-I-OJ-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, N/mm (kgf/mm)
	wire
ka- nata	center- flax	first layer (inner)	second layer (outer)				Breaking force N, at least
	6 wire- lok	36 wires	36 wire- lok	36 wire- lok			total of all wires in rope	rope generally

Continuation

Notes:

1. Ropes, the breaking force of which is given to the left of the thick line, are made from uncoated and galvanized wire. Ropes made of galvanized wire of groups Zh and OZH with diameters of 51.0 and 56.0 mm of the marking group 1370 N/mm (140 kgf/mm), 42.0-47.5 mm of the 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 of the marking group 1770 N/mm (180 kgf/mm), 11.0-16.5 mm of the marking group 1960 N/mm (200 kgf/mm) are produced by agreement between the manufacturer and the consumer.

Ropes, the breaking force of which is given to the right of the thick 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 over 10 mm are rounded to the nearest integer or 0.5 mm.

2, 3. (Changed edition, Rev. N 1, 2).

4. Technical requirements, acceptance rules, test methods, marking, packaging, transportation and storage in accordance with GOST 3241-91.

Electronic text of the document
prepared by Kodeks JSC and verified against:
official publication
Steel ropes. Assortment: Collection of GOSTs. -
M.: Standartinform, 2011

The construction of buildings, bridges and roads, the oil and gas processing and coal industries, sea and river navigation and other industries cannot do today without a steel cable. Flexible and durable steel wire ropes are used for lifting and moving various equipment, building materials, structural elements and other goods.

Features of the structure of the cable

Steel rope is a complex metal product, which is the main element in many road-building, earth-moving, lifting machines and mechanisms. Any cable consists of many wires twisted into strands, braiding a common core made of metal or other materials.

The strength and design of the rope depends on the number and thickness of wires in each strand, the number of cores and their material, the density and number of twists in the rope. The core of the twisted cable forms a model of the finished product and protects the surface of the cable from being squeezed under high mechanical loads. The metal core increases the structural strength of the cable, while under tension and at high temperatures it reduces its structural elongation.

Rust control

The main problem of steel cables, corrosion, is solved in three ways:

The production of the original wire is carried out from of stainless steel. The method is the most reliable and expensive.
Coating of wires with zinc or chromium. The most resistant spraying is designed for several years of operation.
Combined ropes with organic or synthetic core. Lubricated hemp, sisal, manila or cotton cores minimize friction between rope elements and extend rope life. A stronger and lighter two-layer polyamide core is used in cables for extreme sports equipment.

In terms of durability - quality - price, galvanized cables with non-metallic cores are considered the most optimal. Sometimes it is provided with a water-repellent lubricant (solid oil or nigrol).

Quality characteristics of a steel cable

One of the main aspects of evaluating a steel cable is its strength. Determined by the thickness, method of manufacture and design, the strength of the rope determines the permissible load on it. Working strength (permissible force) is determined by the maximum load at which the integrity of the cable is not violated for a long time. Tensile strength is determined by the minimum load that destroys the steel cable. Without collapsing, ropes made of steel with a thickness of 2 ... 10 mm can withstand loads from 47 to 174 kg. The minimum load to break steel cables ranges from 235 kg for thin 2 mm ropes to 5880 kg for ropes with a diameter of 10 mm.

An important criterion when choosing a cable is flexibility. The more wires are twisted into a strand of steel rope, the more flexible it is. In cables of increased flexibility, each of the 6 strands braiding the organic core has a retinue of 144 wires. consists of 72 42 elements is considered rigid. In the production of steel ropes, a wire with a thickness of 1 ... 8 mm is used.

Varieties of steel ropes

The classification of cables is determined by the number of lays:

With a single lay, the wire is wound in a spiral onto the core. This rope can also be used as ready product, and as an element of more complex cables.
For a double lay, ready-made single strands are used, wrapping around the core in a certain sequence. This technique is used for the production of single-layer and multi-layer cables. Special rules wrappings allow double galvanized cables (strands) not only to withstand significant loads, but also not to twist during operation.
The strongest and most reliable ropes are triple stranded. For their formation, strands are produced according to a special method.

The direction of the strands when twisting can be either right or left.

Rope marking

The designation of the type of galvanized cable is determined by the type of weaving of the strands. Depending on the way the wires are arranged, the cables are divided into several types:

LK - linear touch, in which the lay pitch in all layers is the same with a repeating pattern.
LK-O - when weaving a strand, a wire of the same diameter is used.
LK-R - the cable is formed by strands woven from wires with different diameters.
LK-RO - in the manufacture of a rope, strands of different types are woven.
TK - point touch wires. With such weaving, each layer of the strand has its own pitch, and the layers intersect with each other.
TLC - a combined cable made of strands with both linear and point contact.

The correct choice of a galvanized cable, depending on the operating conditions and its purpose, affects the durability and quality of the machines and mechanisms in which it is used. For example, the low density of the internal structure of TK types under dynamic load provokes strong friction of the rope layers and leads to its rapid wear.

The product marking also indicates the type of coating, diameter, type of lay, purpose, type of twist, straightening, accuracy and strength.

The state standard defines the requirements for a galvanized cable, GOST has each type of steel cable. For example, steel cables type LK-O double lay with a metal core are produced in accordance with standard 3066-80, and with organic - 3069-80, LK-O single lay corresponds to standard 3062-80, cables LK-R with an organic core are produced in accordance with GOST 2688 -80 and so on. These documents govern the appointment, mechanical properties grades, types of wire coating, lay direction and method, combination of lay directions of its elements in the rope, manufacturing accuracy and degree of balance. acceptance rules, technical requirements, marking, test methods, packaging, transportation and storage standards for cables are determined by GOST 3241-91.

Application of steel rope

Due to their reliability and practicality, galvanized steel wire cables are actively used as an integral part of industrial equipment in a wide variety of areas:

in lifting and transport mechanisms;
in road construction, earthmoving and mining units;
in the technology of oil and gas industries;
in agricultural vehicles;
in shipbuilding and other industries.

A wide range of ropes of different diameters and strengths allows you to purchase the appropriate type of steel rope for specific equipment.

According to their purpose, steel cables are divided into two groups: those intended only for working with loads and for lifting or transporting both people and goods.

Advantages of galvanized ropes

Coating steel wire with zinc increases the service life of the steel rope by 3 times and allows it to be used in aggressive environments. Galvanized cables are distinguished by a high level of corrosion resistance, which makes them suitable for use on river and sea vessels. Due to their high wear resistance, they are actively used in all areas of industry.

The coating of steel wire with zinc divides the cables into three groups according to working conditions:

In a harsh hostile environment.
In a particularly aggressive harsh environment.
In a medium aggressive environment.

Sheathed cable

The modern industry offers a galvanized cable in a PVC sheath, which increases the protection against corrosion. Such ropes are successfully used when it is necessary to tie a load for immersion in a liquid, as stretch marks during the installation of antennas and masts, during rigging and loading operations in adverse conditions and at low temperatures. A 3 mm galvanized cable in a PVC sheath is used for overhead communication lines and power supply. Today, the range of galvanized cables is replenished with products coated with materials that can withstand high temperatures and resist combustion.

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