Line marking. Slings, traverses, grips and their varieties. production of slings - rope, chain, textile Marking of steel slings

Chain slings, with all their positive qualities (concerning, first of all, carrying capacity), are still not mobile enough, and are distinguished by a noticeable dead weight. At the same time, in many cases, the slings require the convenience of fixing loads, and of very different configurations. These qualities are possessed by textile slings.

Materials of textile slings

Modern textile slings are made from durable artificial fabric compositions that are insensitive to temperature changes, have high elasticity and sufficient tensile strength. The choice of fabric chemical compositions for the manufacture of slings is based on the unconditional fulfillment of the requirements of RD 24-СЗК-01-01, which specifies the mechanical requirements for these products. The starting material is a tape, which is made from chemical fibers of one of three types - polyamide (PA), polyester (PES), polypropylene (PP). The main requirements for the above materials are as follows:

The limiting temperature of the surface of the load, which is fixed with slings, should not exceed 100ºС;
The minimum temperature of the cargo should not be lower than -40ºС;
The residual deformation of the material after using the slings should not exceed 10 ... 15%;
At temperatures exceeding 160 ... 170ºС, the slings should not ignite, but only melt with slight deformation;
The coefficient of relative water absorption of sling materials cannot be higher than 2 ... 4%;
Textile slings must be resistant to acids, alkalis and other aggressive environments;
Belts must not absorb grease, oils or other fats.

The use of other materials for the production of textile slings - in particular, nylon, polypropylene, lavsan, etc. - is allowed only when the actual values of the above parameters are obviously lower than the calculated ones by 20 ... 30%. Polypropylene fibers are not recommended for use in slings that are designed for handling flammable goods.

The industry regulations for the safe use of elastic lifting devices also set requirements regarding the mechanical strength and integrity of textile slings. It is not allowed to have such defects on the surface as a partial cut of individual fibers, their abrasion, burn-through, twisting and residual deformation above the maximum allowable. You can not use threads from another material to connect the lines, and the principle of weaving the tape should minimize its mechanical wear.

To increase durability, textile slings are sometimes covered with protective tapes. Such tapes should not reduce the established limit of tensile loads, provide a snug fit to the main material of the sling, regardless of the nature of the load, and also reduce friction between the sling and the load when it is fixed on the vehicle.

Types and classification

A textile sling consists of two loops and a tape - a free piece of material between the loops. The length of the tapes determines the technological possibilities of slinging the load. Practical application was found by two types of textile slings - loop and ring. Technologically, they differ in a different way of attaching the loop part to the tape part.

Loop slings (designated STP) can be made in three ways:

Through stitching the tape with its wrong side without prior twisting.
Formation of a loop by twisting the end strip part into a Möbius ring, as a result of which the width of the loop decreases and its rigidity increases.
Folding the tape part in half, which accordingly increases the strength of the loop, but is accompanied by an increased consumption of material.

Since the hinges take on the entire load, and also directly contact the crane hook, a double hinge will have the greatest durability, and a flat one will have the least.

Textile ring slings (designated STK) have an oval cross section and are characterized by increased rigidity. However, their adhesion to the surface of the load is worse than that of tape slings. Such slings are used for fixing long loads. Their price exceeds the price of tape slings by 10 ... 20%. For a softer coverage, ring slings are made with round strands and are marked with the designation STKK.

Textile slings are often equipped with oval steel rings, which, using connecting brackets, hang the slings on the crane hook. The use of such rings reduces the wear of the loop. For the manufacture of rings, construction medium-carbon steel grades 30GS or 40G2 are used, which are hardened. Depending on the number of such rings, single and multi-branch slings are distinguished. The load capacity of the latter with the same width, thickness and method of attaching the ends is always higher. In addition, multi-branch textile slings distribute the load more evenly over the contact surface of the hook, and contribute to a more reliable fixation of the ring in the mouth of the hook.

The classification of textile slings is carried out not only according to their performance, but also according to the permissible load capacity. In particular, single-branch textile slings are produced in a width range from 30 to 3000 mm, with a length of 0.8 to 3 m. They allow you to safely fix loads weighing from 500 kg to 20 tons. The permissible deflection height of such slings in the loaded state should not be less than 2 m, since in this case the angle of coverage of the load goes beyond safe limits (no more than 120º is allowed). The number of branches is indicated in the marking of the sling: for example, the designation 1STK indicates a single-branch circular textile sling, 4STP - a four-branch tape, etc. With an increase in the number of branches, the length of the sling decreases, which is associated with an improvement in the conditions for covering the hook with several rings at the same time.

Textile slings are also classified according to the number of layers of the tape: with increased loads, they can be two- or even three-layer. As a result, the allowable load can be increased by 40…50%.

An important element of marking textile slings is their color. It indicates the maximum load capacity of the device:

Purple - load capacity not more than 1000 kg;
Green - load capacity no more than 2000 kg;
Yellow - load capacity not more than 3000 kg;
Gray - load capacity no more than 4000 kg;
Red - load capacity no more than 5000 kg;
Brown - load capacity no more than 6000 kg;
Blue - load capacity no more than 8000 kg;
Orange - carrying capacity of more than 10,000 kg.

Rules for the inspection and culling of textile slings

The frequency of inspections depends on the intensity of use of textile slings. With their rare use, it is enough to visually verify that there are no surface defects. However, if the devices in question are used daily, their revision should be performed at least three times a month, which is regulated by industry regulations.

Each sling is supplied with tags, which indicate the date of the previous check and the permissible test force (it must exceed the nominal one by at least 7 times). During the test, the following is established:

Condition of tapes, rings and connecting brackets.
Serviceability of snap-in elements: carabiners, hooks, etc.
The presence of a distinct stamp on the technological capabilities of the lines.
Absence of stains from acids and alkalis, regardless of their area.
No delamination of multilayer slings (allowed for a length of not more than 200 mm along the middle row and 100 mm along the outer row).
Absence of any surface cracks on steel parts.

Slings with cuts (both longitudinal and transverse), knots and breaks, the length of which exceeds 100 mm, should not be allowed to be used. There should be no burns or holes on the tapes.

The tags of textile slings indicate the value of the test load, GOST or TU, according to which the product, material, temperature limits of use, the actual length of the sling and its brand are made. Additional information may also be indicated, for example, on the features of the slinging of individual loads.

The purchase of textile slings should be made only from trusted manufacturers who are systematically engaged in the production of such products. The price of such products ranges from 400 to 1000 rubles. - for simple single-branch slings, from 1500 to 5000 rubles. - for multi-branch and multi-layer.

Steel rope slings (GOST 25573–82) are special lifting devices that are used to move a variety of bulky and heavy loads using cranes and hoisting mechanisms.

1 Two-loop and other metal slings according to GOST 25573

In accordance with the specified State Standard, products from can be of six different types:

ring (two different versions of products are provided) - SKK;
two-loop (two versions) - SKP;
single-branch - 1SK;
two-branch - 2SK;
three-branch - 3SK;
four-branch (two versions) - 4SK.

A loop sling is a piece of rope that is woven into loops from both ends.

Such products are recognized as the most versatile.

They pass without problems when the load is hooked into eyes, frames, holes, rings and other elements of various structures, while forming several branches. Due to the presence of several branches, the carrying capacity of the mechanisms increases, therefore, the efficiency of crane operation also increases.

The two-loop steel sling, as mentioned, is made in two versions. The first execution is marked as SKP1, the second - as SKP2. There are products marked from SKP-0.32 to SKP-12.5 with a length of 100–3000 cm, with a loop length of 24, 32, 40 and 50 cm. this indicator, the division of the slings is carried out), and the value of their breaking design force ranges from 18800–736000 N.

The ends of the described two-loop products can be sealed using two methods:

crimping into a metal or aluminum sleeve;
hand braided.

Very often used in modern enterprises and ring slings. They are performed in an annular (closed) form. The reliability and strength of slinging with the help of such a device is at a high level if the load is tied with a "dead loop". The ends of these sling products are usually closed using manual braiding technology. However, slings with aluminum bushings are also made.

The load capacity of ring devices is in the range of 0.32–16 tons (marking - from SKK-0.32 to SKK-16), breaking force varies from 9400 to 470000 N, loop length - from 80 to 3000 cm, product width - from 5 up to 25 cm.

Slings with one branch (1SK) are products on one end of which a clamp, a pull hook, an end grip or a carabiner is mounted that meet the requirements of State Standard 25573, and on the other - a loop. 1SK are suitable for moving and loading structures with special mounting hooks, frames, hinges and other devices.

Products with several (2, 3 or 4) branches are slings with one steel link, which connects all available branches with each other. Such devices are used in cases where the load needs to be hooked at the same time for 2-4 points. Multi-leg products use special grips and metal buckles for slings, their carrying capacity is not much, but higher than that of single-leg ones.

2 Calculation and manufacture of slings from steel ropes - features

Products made of metal materials are considered universal, which makes it possible to use them in a variety of enterprises at temperatures from -40 to +150 °C. Loop devices are made from round-spinning ropes. They are most often additional slings for products 1SK-4SK (that is, they are used for combined options for lifting and moving goods).

SCM products are recognized as more reliable if they are equipped with a special thimble, which prevents the appearance of excessive residual deformations. Calculations show that the reliability of using ring slings with a thimble is 20 percent or more higher than products without a thimble.

Calculation and design of slings for capturing cargo necessarily includes the following design stages:

development of technical conditions;
formation of design working documentation;
determination of forces in the flexible components of the slings;
selection of the required rope diameters and geometric indicators of additional components of the slings.

The connecting parts of products that are under load (power), as well as clips of carabiners and hooks, are made of steels 09G2S and 15HSND (if the slings will be used in cold climates), or from steel 20 (temperate climates). Parts that do not take the load (half-coupling ring, carabiner plates, hook lock, thrust elements) can be made from St3.

The production process of slings must meet all the requirements set forth in the operating instructions for cranes and the standards for the device of hoisting mechanisms, as well as in GOST 25032–81. The main ones include the following:

all elements of products, as well as slings as a whole, must carry a static load, the value of which is not less than a quarter higher than the nominal;
ropes for slinging products must meet all the points of three State standards - 3079-80, 3071-88, 7668-80 (branch products, in addition, must comply with the provisions of standards 7565-80, 3077-80 and 2688-80);
the margin of safety of grips and other components of the slings to a load of a destructive type must have a coefficient of at least five units;
it is not allowed to splice ropes to obtain one branch, only a whole rope can be used;
the indicator of the strength reserve of ropes to breaking force should be 6 or more units;
thimbles are manufactured according to the requirements of the State Standard of 1972 2224;
during pressure testing, bushings are made of grade 20 steel or aluminum-based alloys (AD1, AMTs, AD31, AD0);
after crimping, no cracks are allowed on the bushings.

3 Acceptance and rejection of steel rope slings

Acceptance of finished products is carried out after a series of acceptance tests. Without exception, all slings are checked for compliance with GOST (we indicated them earlier). But the quality of the crimping of products is determined at two percent of the slings from one batch, if the termination is carried out with a braid, and at 10 percent when crimping is performed.

A separate batch of products consists of slings of the same load capacity and type, made from steel of the same grade, identical geometric dimensions. Finished fixtures are checked for relative elongation, yield strength, hardness index of hooks and links, lack of penetration of metal, and correctness of welds. The index of toughness (shock) of steel (according to standard 9454) is also established. and finished products is carried out when the results of repeated analyzes for any of the voiced characteristics are unsatisfactory.

Separately, we add that the manufacturer attaches a special marking tag made of metal to each line (or each line is branded). The stamp or tag contains the following information:

company sign (its name);
date of acceptance tests;
the load capacity of the product.

The slings are rolled into bays, which can be completed in bundles weighing up to 100 kilograms.

One of the most important steps in the manufacturing process of all kinds of slings is marking. Marking (from German markieren, from French marquer - mark, put a sign) - the application of conventional signs, letters, numbers, graphic signs or inscriptions on an object, in order to further identify it, indicate its properties and characteristics.

It is the labeling of the product that makes it possible to identify it without any extra effort. Although some types of slings have additional features that can be used to determine the characteristics of a particular product, there is nothing easier than looking at the tag. It should be especially noted that the absence of a marking (tag), as well as the inability to read the information indicated on it, is the basis for the rejection of slings.

Guidance Documents

In this article, we will show the main methods and methods for marking slings used by domestic and foreign manufacturers. Methods for marking slings and the information necessary for placement on tags in Russia are determined by GOST 25573-82, RD 10-33-93, RD 24-SZK-01-01, as well as the manufacturer's specifications.

Clause 7.1. GOST 25573-82: “Each sling must be branded or firmly attached with a metal tag indicating: the name or trademark of the manufacturer; sling number according to the manufacturer's numbering system; lifting capacity of the sling; test date (month, year).

More detailed information about the marking is given by RD 24-СЗК-01-01: “7.1. Each sling must be provided with a marking tag, which indicates: the trademark of the manufacturer, address; type, symbol of the sling; lifting capacity of the sling, depending on the methods of slinging; length; date of manufacture; serial number of the sling according to the numbering system of the manufacturer; designation of technical conditions or standard according to which the sling is made. The inscriptions can be located on both sides of the tag.

7.2. Marking is applied with indelible paint on a special tag made of durable fabric and treated with a protective compound. The color of the marking paint is set by the working design documentation, must differ from the color of the tag material and be clearly visible during the use of the sling. Basically, dark colors (black, blue, green, red) are chosen for marking a light tag. In some cases, for dark tags, white can be used as a marking color. It is allowed to mark textile slings with indelible paint directly on the sling tape in places least subject to abrasion. The dimensions of the marking and the method of application must ensure the safety and readability of the inscription until the end of the sling's operation.

7.3. The dimensions of the tag and its location must comply with the working design documentation.

Tags material

As can be seen from these extracts, the form and material from which the tags should be made are not clearly defined. The main requirements relate to the list of necessary information on the tag and the ability to read it throughout the life of the sling.

In the manufacture of metal slings (rope and chain), metal tags are most often used for marking. As a rule, these are stamped products made of aluminum, alloyed or galvanized steel. Application of information is carried out by shock or shock-dot method. Quite often there are tags with information printed by thermal printing, thus obtaining blanks, while key information (number, load capacity of lines, date of manufacture, etc.) is applied by impact.

Metal tags are not used for marking textile tape and round slings, as they can damage the feet during operation. An alternative is tags made of vinyl, polypropylene, natural or artificial leather. Information is applied by thermal printing using indelible ink.

Tags shape

Since the shape of the tags is not clearly defined, manufacturers choose it themselves. The most common are simple-shaped tags - square, rectangle, circle, oval - they are easy to manufacture and many enterprises make them on their own.

To emphasize the corporate identity, a number of enterprises use curly tags for marking. For example, tags in the form of hexagons and octagons are quite common, there are also more complex design solutions.

As a rule, the shape of the tag does not carry a semantic load, but sometimes designers also find practical applications for them. For example, RUD chain slings have special cutouts that allow a preliminary analysis of the condition of the chain without the use of tools. Naturally, this is a rough estimate, but the identification of deviations may be the reason for a more thorough inspection and rejection of the slings.

Location of tags

For each type of sling, there are common and specific places for attaching tags associated with the features of their manufacture.

In the manufacture of rope slings, tags are strung on a rope and then loops are formed, while the tag can be located both on the body of the sling and on the loop. This method is used in the production of rope slings by both the crimping method and the braiding method. Also, when forming loops by braiding, the tag can be strung on one of the strands of the rope, so the tag is woven into the body of the sling.

On chain slings, the tag is attached to the suspension link, or to the first connecting element. Most often, the tag is located on the LL type connecting link or shackle, this is the most convenient place when assembling the sling.

In the case of textile and round slings, the tag is placed in the places where the tapes are fastened (covers of round slings). In the manufacture of loop slings, the marking tag is located at the base of the loop.

Guiding documents allow the placement of markings and additional information on the body of tape slings. Since the size of the tag is not regulated, in addition to the mandatory information, the manufacturer often indicates the carrying capacity of the sling for various sling options, warning and other reference information.

06.11.2015 To date, slings (textile, rope, chain) are used everywhere and there are many designs of slings used in accordance with the purpose and nature of the goods. Each type of slings has its own characteristics of the device and operation, they are characterized by certain advantages. But the marking of the slings is mandatory for all varieties, and in its absence, the use of a sling to lift any cargo is strictly prohibited.
In any situation, it is not worth neglecting the issues of monitoring the presence of sling markings. After all, its presence is stipulated by the requirements of GOST, PUBEGC and is a guarantee of the safety of personnel servicing lifting mechanisms during loading and unloading operations.
The marking of rope and chain slings is applied by impact on marking tags cut out of a steel sheet about one millimeter thick, woven into the sling or suspended from it on a metal fastening ring.
Marking data includes information about the name of the company that manufactured the sling (with its trademark applied), the number of the sling according to the factory classification, its load capacity in tons. In addition, the month and year of the sling test (date) are mandatory.
It is the labeling of the product that makes it possible to identify it without any extra effort. Although some types of slings have additional features that can be used to determine the suitability for the use of a particular product, the information on the marking tag contains complete information about the product. In case of loss of the marking tag and the absence of the above information on the link of the sling, the sling is withdrawn from operation.

Regulations

GOST 25573-82:

7.1. Each sling must be branded or firmly attached with a metal tag indicating:

Name or trademark of the manufacturer;
- sling number according to the manufacturer's numbering system;
- lifting capacity of the sling;
- test date (month, year).

RD 24-SZK-01-01:

7.1. Each sling must be provided with a marking tag indicating:

Trademark of the manufacturer, address;
- type, symbol of the sling;
- lifting capacity of the sling, depending on the methods of slinging;
- length;
- date of manufacture;
- serial number of the sling according to the numbering system of the manufacturer;
- designation of technical conditions or standard according to which the sling is made.

The inscriptions can be located on both sides of the tag.
7.2. Marking is applied with indelible paint on a special tag made of durable fabric and treated with a protective compound. The color of the marking paint is set by the working design documentation, must differ from the color of the tag material and be clearly visible during the use of the sling. Basically, dark colors (black, blue, green, red) are chosen for marking a light tag. In some cases, for dark tags, white can be used as a marking color. It is allowed to mark textile slings with indelible paint directly on the sling tape in places least subject to abrasion. The dimensions of the marking and the method of application must ensure the safety and readability of the inscription until the end of the sling's operation.
7.3. The dimensions of the tag and its location must comply with the working design documentation.

Tags material

In the manufacture of rope and chain slings, metal tags are used for marking. These are stamped alloy steel products. Application of information is carried out by shock or shock-dot method.

Metal tags are not used for marking textile tape and round slings, as they can damage the feet during operation. Vinyl tags are an alternative. Information is applied by thermal printing using indelible ink.

Location of tags

For each type of sling, there are common and specific places for attaching tags associated with the features of their manufacture.
When forming loops of rope slings by braiding, the tag is strung on one of the strands of the rope, so the tag is woven into the body of the sling.

In the manufacture of rope slings by crimping, the tags are strung on a rope of smaller diameter and then a loop with a tag is formed.

On chain slings, the tag is attached with a clamp to the suspension link, or to the first connecting element. Most often, the tag is located on the LL type connecting link or shackle, this is the most convenient place when assembling the sling.

In the case of textile and round-strand slings, the tag is placed in the places of stitching (adhesion) of the tapes (covers of round-strand slings). In the manufacture of loop slings, the marking tag is located at the base of the loop.

Guiding documents allow the placement of markings and additional information on the body of tape slings.

Slings are called segments of ropes or chains that are fastened in a special way. The slings are provided with suspension devices that help to fasten the load quickly and conveniently. Slings are marked without fail: if there is no information on the tag, or it cannot be read, such slings are considered defective.

Marking is the application of inscriptions, symbols, drawings on an object. Marking helps to identify an object without any extra effort: it fixes its characteristics, properties, features.

Documents defining labeling requirements

The procedure for marking cargo slings in Ukraine is determined by the current legislation. The key document of the industry is DSTU B V.2.8-10-98. It is written in it:

requirements for the manufacture of cargo, multi-branch slings;
sling testing procedure, safety factor;
rope requirements: materials, types, strength;
requirements for labeling and mandatory information in the product passport.

So, the document says that a tag must be attached to each line. In addition, the way it is attached must be such as to ensure the safety of the marking until the end of the life of the sling.

The label on the tag contains:

name of the manufacturer;
load capacity of the product;
serial number of the product;
month and year of manufacture.

In addition, the sling is applied to each link and hook by the impact method: manufacturer's name, permissible load, year of product testing (in the format of the last two digits).

The product data sheet contains more detailed information. So, here, in addition to the above information, the length of the product, the number of them in one batch, the results of inspections and tests should be affixed. In addition, the passport indicates the warranty.

Another document that specifies the requirements for marking slings is TU U 29.2-22959884-011:2005. The technical specifications indicate the requirements for marking chain slings. In addition to the information provided for by DSTU, the tag must indicate:

strength class;
the number of turns and the caliber of the chain (shot);
indication of technical conditions of manufacture;
conformity mark DSTU 2296 (for certification).

What should be the tags

The legislation provides for requirements for the content of the marking and its quality: the marking must remain legible throughout the entire life of the sling. Tag material may vary. For chain slings, the material of the tags is provided for by the specifications - they must be metal without fail.

The tags are stamped, and then the necessary information is applied by impact. Some tags are thermally printed with information, but then the key information required by law is applied with an impact method.

Metal is not used when marking textile tape and round slings, as it can damage the slings during their operation. For such products, leather or synthetic tags (high-strength plastic) are used.

On tags made of leather or synthetic materials, the necessary information is applied using thermal printing. Indelible ink is used for marking.

Manufacturers independently determine the shape of the tags. Most often they are simple: oval, square, circle. Curly tags are used by those companies that want to emphasize corporate identity: hexagonal, octagonal and more design solutions that can carry additional functional load.

Location for tags

Locations for attaching tags can be general or specific. The method and place of fastening are determined by the technology used for making slings, what material is used.

In the manufacture of chain slings, the tag is attached to the first connecting element, or bracket. Another option is to attach it to a hanging link. On rope slings made both by crimping and riveting, tags are placed either on the body of the sling or on the loop. In the manufacture of round-spinning, textile slings, the tag is attached at the place where the tapes are fastened. On loop slings, the tag is placed at the very base of the loop.

Slings are marked in the manner prescribed by law. The marking must be clear, legible and reliable: the tag serves throughout the entire life of the product. Proper marking of slings is a guarantee of their high quality and durability, confirmation of the reliability of the manufacturer.