Rejection of slings - norms and rules. Chain slings. Types and norms of rejection How to write off slings

Slings are rejected: in the absence or damage of the brand (tag); in the absence of safety locks on the hooks; in case of malfunctions of the end elements (presence of cracks, wear of the surface of the elements or local dents, leading to a decrease in the cross-sectional area of ​​​​more than 10%); in case of deformation of the thimbles or their wear with a decrease in the cross-sectional dimensions by more than 15%; if there are cracks in the bushings or if the size of the latter changes by more than 10% from the original; if there are signs of rope displacement in the braid or bushings; in the presence of protruding ends of the wires at the place of braiding, in the presence of a break in at least one strand, in the presence of mechanical deformations, breakage or extrusion of the core, a decrease in the diameter of the outer wire by 40%, a decrease in the diameter of the rope by 7% due to surface wear or corrosion, in case of damage due to the effects of arc discharge or temperatures. Rope slings must be rejected along the length of the section: 3d - 4 breaks; 6d - 6 breaks; 30d - 16 breaks, in the presence of a malfunction of links, hooks:

a) the presence of cracks;

b) wear of surface elements that reduce the cross-sectional area by 10% or more;

c) residual deformations that change the original size by more than 5%

4. Production of work with two cranes

Loading and movement of goods by several cranes (two or more) are allowed in some cases: if the owner of the crane does not have the necessary lifting capacity or when the nature of the load does not allow the use of the existing lifting capacity.

Such work should be carried out in accordance with the PPR or technological map, which provides slinging and movement of goods with an indication of the sequence of operations performed, the position of the cargo ropes, as well as instructions for the safe movement of goods. In this case, the load falling on each crane, taking into account the mass of the cargo and the mass of the lifting devices, should not exceed its lifting capacity. The load must be strictly horizontal, slings, ropes, hooks in the design position. Work by machinists must be carried out strictly synchronously, at the minimum allowable uniform speed. When the load is skewed, a lowering command is given.

All work is supervised by the responsible person of the workshop for the safe performance of work by cranes

The stencil of the crane contains: the registration number of the crane, the lifting capacity, the date of the next partial (WHAT) and full (PTO) technical examination.

Exam ticket number 7

1.Main causes of accidents

During the performance of work with cranes, accidents and accidents periodically occur, the main causes of which are:

equipment malfunction;

incorrect (unreliable) slinging of cargo;

use of unsuitable load-handling devices and containers for lifting cargo;

presence of people in the area served by the crane;

violation technological maps loading and unloading operations;

the presence of people in a gondola car, on a platform, in the back of a car, in a well when lifting or lowering a load;

non-observance of schemes and dimensions of warehousing of goods;

presence of people in the cab of the vehicle during its loading or unloading;

lifting of "dead" cargo;

presence of people near the wall, column, stack or equipment during the lifting or lowering of the load;

pulling the load with a crane with an inclined position of the cargo ropes;

presence of people in the area of ​​the clamshell crane;

breakage of ropes;

poor health of the driver or slinger;

non-compliance with the Rules for technical operation and safety regulations.

The rejection of tape slings produced according to RD 24-S3K-01-01 is mandatory in the following cases:

In the absence of a tag on the sling or unreadable information about it.

If there are knots on the carrier tapes of the textile sling

In case of transverse cuts or breaks on the tape of the textile sling

In the event that there are longitudinal breaks or cuts on the tape of the textile sling with a total length of more than 10% of its entire length, as well as in the presence of single cuts or breaks with a length of more than 50 mm.

· In the presence of local bundles of the tape of the textile sling (except for the places of sealing the edges of the tape) on a length of more than 0.5 m in total on one of the extreme or on two or more internal seams. (in case of rupture of three or more seam lines).

· If there are local bundles of tapes of a textile sling in the place of sealing the edges of the tape over a length of more than 0.2 m. on one of the extreme seams or on two or more internal seams (in case of rupture of three or more lines of the seam).

· In case of detachment of the edge of the tape or stitching of the tapes at the loop for a length of more than 10% of the length of the sealing of the ends of the tape.

· In the presence of surface breaks in the threads of the tape, formed by friction of the sling on the sharp edges of the load, the length of which exceeds 10% of the total length of the tape.

In case the tape is damaged by impact chemical substances(acids, alkalis, oil products) with a total value of such damages of more than 10% of the length or width of the textile sling or in the case of single damages of more than 10% of the width of the sling and more than 50mm. length.

· When threads bulge out of the textile sling tape at a distance of more than 10% of the tape width and in the presence of through holes from sharp objects, the diameter of which exceeds 10% of the tape width.

· In the presence of burnt holes from splashes of hot metal, the diameter of which is more than 10% of the width of the tape, as well as in the presence of more than three through holes with a distance between them of less than 10% of the width of the tape (regardless of their diameter).

· If the belt is contaminated by more than 50% with oil products, resins, paints, cement or soil, the sling must be rejected immediately.

· At stratification of threads on tapes of a textile sling.

If any of these signs appear, textile slings are culled, because. their subsequent operation is unsafe.

It is forbidden to repair the textile sling on your own.

On the structural elements of the textile sling (such as staples, rings, loops, pendants, links, etc.) are unacceptable:

1. cracks of any size - the rejection of such slings is obligatory, cracks cannot be reduced and eliminated.

2. surface wear or dents resulting in a reduction in the cross-sectional area of ​​the element by 10% or more.

3. Deformations of the element, leading to a change in its original size by more than 3%.

4. Damage to fasteners and threaded connections. Rejection of slings is obligatory, according to the governing document.

You should also observe the service life of textile slings.

Textile slings are tested with a static load, which exceeds the carrying capacity of the sling by 1.3 times for 3 minutes. Textile sling is made in accordance with RD 24-S3K-01-01. The correct operation of the textile sling is guaranteed when working in one shift for 1.5 months from the date of commencement of its operation. The shelf life of a textile sling is 6 months from the date of its manufacture, subject to proper storage and operation.

Steel rope slings are not allowed to work (i.e., such rope slings must be rejected or repaired or disposed of) manufactured in accordance with GOST 25573-82 and RD-10-33-93 in the following cases:

Lack of a passport for the sling or tags with the specified information about the sling

· If there are knots, kinks, creases on the cable or when the cable is twisted.

In the event that the diameter of the cable has decreased due to wear or corrosion by 7% or more

In the event of a decrease in the diameter of the outer wires of the cable due to wear or corrosion by 40% or more, the sling is simply dangerous, the rejection of such a sling is necessary immediately

· In the event of a strand of rope breaking.

When squeezing out the core of the rope

If the lanyard is damaged by temperature or electrical arcing

· If the thimble of the sling is deformed, the culling of the sling must be carried out without delay. This stop is already dangerous.

If the wear of the thimble section exceeds 15%

If there are cracks on the crimping sleeve or a change in its dimensions by more than 10%

In the absence of safety locks on hooks or other load-gripping elements of the rope sling

If any of these damages occur, the rope slings are rejected. Continued use of such a sling is dangerous.

It is forbidden to repair the rope sling on your own.

On the structural elements of the rope sling (such as links, hooks, hangers, etc.) are unacceptable:

3. deformations leading to a change in the dimensions of the sling element by more than 3%.

4. Damage to the fastenings of elements and threaded connections.

You should also observe the service life of rope slings.

Rope slings are tested with a static load, which exceeds the carrying capacity of the sling by 1.3 times for 3 minutes. Rope slings are manufactured in accordance with GOST 25573-82 and RD-10-33-93.
The correct operation of the rope sling is guaranteed when working in one shift for 3 months for USK1 (SKP) and USK2 (SKK) slings and 6 months for branch slings and VK type slings (the time is considered from the day the rope sling was put into operation).

Rejection of chain slings - rules and regulations

The rejection of chain slings produced in accordance with PB-10-382-00 and TU 3150-001-52466920-2005 is mandatory if:

In the absence and damage of the label of the sling, as well as in the absence of a passport for the sling

In case of unreadable markings on the elements of the sling

If the difference in the lengths of the branches of the sling during the free sag is more than 15mm - the culling of the sling is required

In the event that the chain link, connecting links and hangers are extended by more than 5% of their original size

If, due to wear, the cross-sectional diameter of chain links or connecting links has decreased by more than 8%

In the absence of safety locks on the hooks or load-gripping elements of the chain sling

If any of the listed defects is detected, the chain slings are rejected, further use not safe.

Self-repair of chain slings is prohibited.

On the structural elements of the chain sling (such as brackets, hooks, connecting links, etc.) are unacceptable:

1. cracks of any size, delaminations, tears and hairlines

2. surface wear and dents that lead to a decrease in the cross-sectional area of ​​the elements of the sling by 10% or more

3. deformations leading to a change in the dimensions of the sling element by more than 5%

4. Damage to the fasteners of elements and threaded connections is a clear sign of the need to reject slings.

The rejection standards for steel ropes used on towers, elevators, winches, funiculars, cranes, cable cars and other lifting structures are set out in Guidance Document 012-97.

1 Rules for the control of steel ropes

RD 012-97, in accordance with which ropes are rejected, is recommended for the manufacture, operation, examination, design, installation and repair of lifting installations for all individuals, enterprises, foreign companies operating in the Russian Federation, organizations. According to this document, control is carried out:

• periodically: every 10 days;
• every shift: before using lifting structures.

Special inspections with the use of flaw detectors are also provided.

Such inspections are obligatory during technical examinations.

They allow you to control the loss of section, the presence of rust, possible breaks and wear of the outer and inner wires of the product. Note that all these inspections are carried out regardless of the type of lifting structure on which the rope is installed.

During inspections, increased attention is paid to the following areas of the rope:

• mounts on the cab, drum, counterweight;
• sections that pass through leveling, fixed and movable blocks;
• internal parts, where increased wear of the structure is usually recorded;
• areas for sealing the ends of the product.

• indirect (in other words - deformational): it is understood that the technical condition of the product is assessed by an integral method for angular and linear deformations;
• visual: examination by a specialist who can use special means (in particular, certain optical devices);
• flaw detection: devices (defectoscopes) are used for ultrasonic, x-ray and magnetoscopy;
• instrumental: measuring tools are used, with the help of which such product indicators are measured as deviations from the straightness indicator, wire wear, rope cross-section.

2 Rejection of steel ropes - all its criteria

The safe use of products is determined according to the following criteria:

• internal and surface wear;
• the nature of the wire breaks and their total number at the specified length;
• local decrease in the rope cross section (situations when a core break is noted are also taken into account);
• corrosion manifestations (internal and surface);
• active elongation of the residual type after running in the product;
• the presence of zones of concentration of wire breaks;
• rupture of strands (one or more);
• changes in lay size;
• the presence of deformations, expressed by extrusion of strands and wires, waviness, kinks, corrosiveness, creases;
• exit from the lock of the outer wires;
• the presence of damage caused by an electric arc discharge, exposure to high temperature;
• reduction of the internal section (transverse diameter of the wires).

The rope is immediately rejected in the following cases:

• With a decrease due to wear of the cross section of the wires located outside, by a value of 40%. The length of the wear area is not taken into account.
• In the case of a reduction in the cross section of the steel rope, caused by corrosion or wear (surface), by 7 or more percent in relation to the nominal diameter (even in cases where the wires do not have visible breaks). If breaks or internal wear have damaged the core of the product by 10% of its nominal size, the rope is also rejected (for low-rotation products, rejection should be carried out at a rate of 3%).
• When a wire breaks (this is also understood as a situation where one wire wears out by 40%).
• An increase in the section of the product by 7% (the phenomenon is very dangerous, since it is caused by the swelling of the core under the influence of high humidity, and then its freezing when the air temperature drops).
• The loss of strength of the wires is higher than the standards allowed for each individual type of lifting equipment. This loss is determined by a decrease in the cross section of the wires (verification is carried out by the flaw detection method).
• Flattening the product along the length. It is caused, as a rule, by significant wear of the block stream.
• With waviness, described by an excessively high helical shape of the longitudinal axis of the rope. Of particular danger is the situation in which the directions of the lay of the steel product and the spiral coincide.
• Extrusion of three or more wires, fixed on a rope length equal to its six diameters. In fact, extrusion is a delamination of the structure, which occurs when the wire friction index is high.
• When detecting (visual analysis) creases, twisting, basket-shaped deformation, kinks. With all the voiced defects, the product loses its strength, and significantly.

3 Important standards for rejecting steel ropes of various lifting mechanisms

The elongation of a steel product by more than 5 percent of its working length is considered a rejection criterion. On ropes that are used on rubbing pulleys, the residual elongation always increases fairly quickly. This causes one of the ropes of the mechanism to slip (even when the pulley is equipped with a tensioner).

Guy ropes and load-bearing products are rejected when the initial length of the section, which is six diameters of the product, increases by 9 percent during operation. Such an indicator indicates that there are absolutely critical deformations in the rope that can cause torsion of the structure due to wire breaks (internal).

The product is immediately rejected if the thermal effect on it was recorded during the check. Signs of exposure to elevated temperature are the following phenomena:

• the color of the rope in any section is changed;
• the presence of burntness;
• soot residue.

Most often, such symptoms are caused by the influence of electric current, splashes that fall on the structure during welding activities, and the ingress of molten metal onto the rope.

Products mounted on lifting units with a closed design are subject to immediate replacement, in accordance with the steel rope rejection standards, when:

• visually fixed defect of the lock of the wires (external);
• wear by 50 percent or more of the shaped outer wire (the amount of wear is determined by its height);
• 12 broken shaped outer wires over the entire length of the product or 3 over an extent equal to 30 rope diameters;
• exit of at least one outer wire from the lock.

Low-rotation products, which are usually used in elevator equipment, are rejected if there are eight wire breaks with a length of the examined section of 30 diameters and four in a section of 6 diameters. Here it is worth noting separately that when attaching the elevator cabin with two steel ropes, culling is carried out for each of them. If necessary, it is allowed to change one rope, which is more worn out.

When slinging heavy and oversized loads, chain slings are often preferred. They, in comparison with rope ones, have increased flexibility, as well as an extended temperature range of application, which is used when moving “hot” goods. In addition, chain slings are much easier to cull. It is enough to establish the fact of mechanical damage to the material of one of the links.

Marking and load capacity of chain slings

Chain slings have standard design: a chain consisting of several links, two transition links and an optional oval end link, which can be connected to the transition links in a detachable or one-piece way. The key classification feature is the number of chains. This setting distinguishes:

1. Single-branch slings (marked 1STs).
2. Two-branch slings (2STs).
3. Three-branch slings (3STs).
4. Four-branch slings (4STs).
5. Slings in the form of a single chain branch, which can be open (VC) and closed, in the form of a ring (USC-K).

Chain slings of a more complex design are obtained by combining the above types.

Chain slings are also classified according to their carrying capacity, which is determined by the strength classes of individual parts of the device. The higher the strength class, the lower the specific material consumption of chain slings, and the higher their durability.

In practice, slings of the following strength classes are used:

• 3rd class - maximum load capacity at temperatures up to 200ºС - no more than 100 kg;
• 5th class - maximum load capacity at temperatures up to 200ºС - no more than 300 kg;
• Class 8 - maximum load capacity at temperatures up to 200ºС - no more than 800 kg;
• class 10 - maximum load capacity at temperatures up to 200ºС - no more than 1200 kg;
• Class 12 - maximum load capacity at temperatures up to 200ºС - no more than 3150 kg;

Loads are per chain. With an increase in the operating temperature of more than 200ºС, the allowable loads are reduced by 10 ... 15%.

Within each of the classes, chain slings are also distinguished by the diameter of the chain link. The above specifications apply to products where the chain diameter is the minimum value specified by the standard. For example, a chain sling of strength class 10 with a link diameter of not 4, but 22 mm, has an installed load capacity of 22 tons.

There is no GOST for non-mechanized versions of chain slings, therefore their manufacture is carried out in accordance with the regulatory requirements of RD 11-07-2007. The standard designation of these devices includes such characteristics as strength class, code name / type, load capacity established for the temperature range -40º ... + 200ºС and length in mm. For example, the designation 10-4STs-17.0-6500 corresponds to strength class 10, four-branch, with a permissible load on each branch of 17 tons, a length of 6500 mm. The designation may also include additional elements, such as climate class.

Chain slings can be equipped not only with gripping hooks, but also with end stops, which is noted in the product passport.

The strength class of these products is determined by the steel grade from which the chain links are made. For chain slings of classes 3 and 5, the links are made of steel St.3 GOST 380, which is convenient for subsequent welding. In other cases, the links are made from carburized structural steels such as Stal 20 GOST 1050. For particularly difficult operating conditions, links and connecting elements are made from low-alloy building steels such as 18G2S or 20GS according to GOST 19281.

Chain sling 4STs

Complete 4 leg chain slings consist of:

1. Chain branches of the VC.
2. Upper and lower end links, while a hook can be used as the upper link.
3. gripping organ.
4. Intermediate links (used in cases where electric welding, as a method of connecting links, cannot be used).
5. Limiter (used to prevent the lines from opening to an angle that is not recommended for safety reasons).

Range optimal use slings of this type - loads total weight from 2500 kg to 26500 kg (in the first case, the dimensions of the chain link are 6 × 18 mm, and in the second - 20 × 60 mm; the first digit in the designation indicates the diameter of the chain, and the second indicates the length of the link).

Slings 4STs must not be used at temperatures below -40ºС, when the operation of the load gripping device is accompanied by periodic shock loads. To increase the durability of their operation, chain slings can be made with a surface coating using the burnishing method (the so-called "black slings"). As a result of this treatment, a surface film is formed, consisting of high-temperature iron oxides. The presence of such a film blocks corrosion processes, the activity of which especially increases during the operation of chain slings in acidic environments with a pH value<7.

The main indicators that ensure the safe operation of four-branch chain slings are:

• Ultimate load on the chain link. The normative margin of safety is taken in the ratio 4:1;
• The opening angle between the extreme branches, which should not exceed 90º;
• Strength class corresponding to the conditions of use (determines the flexibility of the sling).

Chain slings of type 4STs (in the slang of builders such slings are called "chain spider") are the most versatile version of chain slings, since they fully take into account the non-standard configuration of the load being lifted. Their main operational advantages are:

• Increased maintainability: if plastic deformation of one of the links is detected (creep effect of the material), it is enough to shorten all the branches of the sling by one link;
• Chain stiffness, which is practically independent of the conditions of use;
• The ability to move loads that have sharp edges and edges;
• Convenience during storage (slings of this type are easily folded and unfolded);
• The minimum specific weight of the device, based on the mass of the load lifted with it.

Chain slings 4STs are easily aggregated with other parts of gripping devices, for example, brackets of various types (including those made according to customer drawings).

Chain sling rejection rates

The requirements of intersectoral norms for the safe carrying out of loading and unloading operations RM-07-2008 provide for a periodic check of the performance of cargo slings, including chain slings. Such culling is carried out by authorized persons at least once every 10 days (with the exception of rarely used slings, for which the culling period, in agreement with the Gosgortekhnadzor authorities, can be extended until the next use of chain slings).

Chain slings are inspected to identify defects such as the integrity of chains, hooks, staples, grabs, the presence of surface cracks, partial damage to the weld, etc.

The criteria for rejection of the considered devices are:

1. The absence of a passport for slings, which indicates the year of manufacture of the product, the dates of its previous inspections, the absence of clearly distinguishable markings on the links, and similar information.
2. The difference in the lengths of the individual branches of the sling when it is freely lifted exceeds 15 mm.
3. Branch links are intact, but the length of the link is increased (compared to the standard) by more than 5% of the original value.
4. The transverse value of the chain link diameter in any place of its contact with an adjacent link, shackle or hook is reduced by 8%, and there are signs of wear on the link surface - grooves, local recesses, etc.
5. At least one of the connecting elements of the chain sling is missing safety locks.
6. The metal of hooks, staples, and welded links has an oxide film, surface cracks, hair lines, and the weld is not continuous.
7. At least one of the chain links has transverse deformation, which consists in the rotation of the link relative to the common axis of the sling.

A general check of the carrying capacity of chain slings is performed as follows. The product is loaded with a static force, which is 4 times greater than that indicated in the passport. Removal of force is carried out no earlier than after 3 minutes. A chain sling that, after such a test, has not received the above damage and deformations, is considered fit for further use.

If at least one of the indicated deviations from the norm is detected, the chain sling is rejected, and its repair is not allowed. If the product is under the manufacturer's warranty, then it is replaced with a suitable chain sling of the same design within the time specified in the passport.

The price of chain slings depends on their design and permissible load capacity. For fixtures of the 1STs type, it ranges from 1500 ... 15000 rubles, 2STs - 2000 ... 20500 rubles, 4STs - 4000 ... 60000 rubles. per set.