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Practical code for inspection and scrapping of wire ropes for cranes

Practical code for inspection and scrapping of wire ropes for cranes


GB/T5972-2006/ISO4309:1990

1 Scope
a) This standard specifies the general principles of wire rope inspection and scrapping. This standard applies to the following cranes:
b) Steel rope and gantry cable crane
c) Cantilever crane
d) Deck crane
e) Mast and cable mast crane
f) Diagonal mast crane
g) Floating crane
h) Bridge crane
i) Portal or semi-gantry crane
j) Portal or half portal crane
k) Railway crane
l) Tower crane
These cranes can be operated with hooks, grabs, electric disks, buckets, buckets, container spreaders, stacking forks, etc., and can be operated manually, motorized, electric or hydraulically.
This standard also applies to electric wire rope hoists.
The crane vocabulary involved in this standard can refer to ISO 4306-1;
The classification of institutions involved in this standard can refer to ISO 4301-1.



2 Terms and definitions

The following terms and definitions apply to this standard

2.1
Wire rope core
The part that supports the outer strands of the wire rope. In the structure of 6-strand steel wire rope and 8-strand steel wire rope, the rope core library is made of a natural or man-made fiber rope, a steel wire rope strand or several steel wire rope strands (twisted in a spiral into a single thin steel wire rope).

2.2
Part of the wire rope on the drum
Due to the groove shape of the reel or the shape of the bottom wire rope, the wire rope is wound from one circle to another to change the rope section of its normal track.

2.3
Wire rope inspection record
For records made by users of lifting equipment, typical examples are given in Appendix B.

2.4
gap
There is a gap between the steel ropes in the rope strands or between the rope strands of the same layer in the steel rope.

2.5
Contact point
The contact part between the strands and the wire rope at the contact position may break due to the gap between the strands.

2.6
Multi-layer winding of steel wire rope on drum
The wire rope is continuously wound on the drum to form multiple layers (the multilayer winding is spiral or parallel, the latter refers to the winding type of the wire rope from one layer to the other and the winding type of the wire rope on the drum at the fixed position Consistent).

2.7
Same direction twist
The twist direction of the strands in the steel wire rope is the same as the twist direction of the outer steel wire.

2.8
Twist length
The pitch formed by each strand.

2.9
Multi-layered rope
For a wire rope formed by winding several layers of strands, if the winding direction of one or more layers of strands is opposite to that of the outer strands, the rotation characteristics of the wire rope can be reduced; if all strands are wound in the same direction, there is no such advantage.

2.10
Interactive twist
The twist direction of the strands in the steel wire rope is opposite to the twist direction of the outer steel wire.

2.11
reel
When used for transportation and packaging, the rotatable part of the winding wire rope can be of wooden or steel structure, depending on the quality of the winding wire rope.

2.12
The actual diameter of the wire rope
The diameter of the circumscribed circle of the wire rope.

2.13
Nominal diameter of wire rope
The nominal value of wire rope diameter, unit: mm.

2.14
Torsion resistant wire rope
A spirally wound steel wire rope with more than 8 strands (including 8) in the outer layer, and the winding directions of the outer strands and the inner strands are opposite.


3 Wire rope
3.1 Condition before installation
The user should ensure that the condition of the wire rope meets the requirements of this standard.
The newly replaced wire rope should generally be the same type and specification as the originally installed wire rope. If a different type of wire rope is used, the user should ensure that the new wire rope is not lower than the original wire rope performance and is compatible with the groove shape on the drum and pulley.
When the wire rope on the crane is cut from a longer rope, the cut should be treated to prevent it from loosening.
Before reinstalling the wire rope device, check all the rope grooves on the drum and pulley to ensure that they are completely suitable for the replaced wire rope.

3.2 Installation
When pulling out the wire rope from the reel or wire rope roll, measures should be taken to prevent the wire rope from looping, kinking, bending or sticking to debris.

If friction occurs with a certain part of the machine when the wire rope is unloaded, the parts that can be touched should be properly protected.

Before the wire rope is put into use, the user should ensure that various devices related to the wire rope work have been installed and operated normally.

In order to make the wire rope stable in place, the machine should be operated several times with approximately 10% of the rated load.

3.3 Maintenance
The maintenance of the wire rope should be determined according to the purpose of the crane, the working environment and the type of the wire rope. Where possible, the wire rope should be cleaned and coated with lubricating oil or grease in a timely manner (unless otherwise specified by the crane manufacturer or wire rope manufacturer), especially those parts that undergo bending when bypassing the pulley .

The types of lubricating oil and grease to be brushed should be compatible with those used by the wire rope factory.
Lack of maintenance is one of the main reasons for the short life of steel wire ropes, especially when the machine is working in a corrosive environment, and when it is not lubricated due to work-related reasons.

3.4 Inspection
3.4.1 Period
3.4.1.1 Daily observation
Every working day should try to observe any visible parts of the wire rope in order to find damage and deformation. Particular attention should be paid to the fixed parts of the steel wire rope on the machine. Any obvious change should be reported and inspected by the competent person in accordance with 2.4.2.

3.4.1.2 Regular inspections by supervisors (carried out in accordance with 3.4.2).
In order to determine the inspection period, the following points need to be considered:
a. The country's regulatory requirements for the lifting machinery;
b. The type and working environment of the crane;
c. The working level of lifting appliances;
d. The results of previous inspections and the occurrence of defects;
e. The time the wire rope has been used.
3.4.1.3 Carry out special inspections in accordance with 3.4.2
3.4.1.3.1 In the case of an accident caused by damage to the steel wire rope and (or) its fixed section, or before the steel wire rope is disassembled and reinstalled and put into use, the steel wire rope shall be inspected once.
3.4.1.3.2 The lifting device has stopped working for more than 3 months, and the wire rope should be checked before being used again.
3.4.1.4 When steel wire ropes are used alone or partially on synthetic materials, metal materials or pulleys inlaid with synthetic material wheel linings, when obvious signs of wear are found on the outer layer, a large number of broken wires may have been produced inside. Therefore, a special inspection schedule for steel wire ropes should be established based on previous steel wire rope use records, in which both regular inspections in use and detailed inspection records of steel wire ropes should be considered.
Particular attention should be paid to the maintenance of the local rope segments where the lubricant has dried or deteriorated. For the scrap standard of special lifting equipment, the data exchanged between the lifting equipment manufacturer and the steel rope manufacturer shall prevail.


3.4.2 Inspection site
3.4.2.1 General parts
Although the overall length of the wire rope should be inspected, special attention should be paid to the following parts:
The beginning and end of the wire rope movement and fixation;
In the case of repeated operations of the mechanism through the pulley block or the rope section that bypasses the pulley, special attention should be paid to any part of the pulley that bypasses the pulley during the lifting of the mechanism. See Appendix A (Supplement);

The rope segment on the balance pulley:
Rope segments that may be worn due to external factors (such as hatch rails);
Internal inspection for corrosion and fatigue;
The rope segment is in a hot environment.
The inspection results should be recorded in the equipment inspection record book.
3.4.2.2 Rope end position (except rigging)

The section of wire rope leading from the fixed end should be inspected, because fatigue (broken wire) and corrosion in this part are dangerous. The deformation or wear of the fixing device itself should also be inspected.

Perform similar inspections for rope end fixing devices using pressed or forged rope hoops, and inspect the rope hoops for cracks and the possibility of slippage between the rope hoops and the wire rope.
Detachable devices (wedge joints, rope clamps, pressure plates, etc.) should be inspected for broken wires and corrosion inside and inside the rope ends, and the tightness of the wedge joints and wire rope clamps should be ensured. The inspection should also ensure that the rope end devices comply with the corresponding Standard requirements.
For braided looped buckle type rope heads, only use at the end of the joint to prevent the protruding steel wire from the rope end to prevent hands. The rest of the joint should be checked with the naked eye for broken wires at any time.




Instructions for adoption:
① The content of this item is drafted in accordance with Appendix C of the International Standards and combined with national conditions.
② International standards have no such content.
③ This content originally refers to cranes used on construction sites.
If the wire breakage obviously occurs near the rope end device or in the rope end device, the wire rope can be shortened and reinstalled on the rope end fixing device for use, and the length of the wire rope must meet the minimum number of turns to be wound on the coil.

3.5 Scrap Standard
The safety degree of wire rope use is determined by the following items (see paragraphs 2.5.1—2.5.11);
a. The nature and quantity of broken wires;
b. Broken wire at the rope end;
c. Local gathering of broken wires;
d. Increasing rate of broken wires;
e. The strand is broken;
f. The rope diameter is reduced due to damage to the rope core;
g. Reduced flexibility;
h. External and internal wear;
i. External and internal corrosion;
j. Deformation;
k. Damage caused by heat or arc.
i. Increase rate of permanent elongation.
All inspections should consider the above factors and follow their own standards. However, the damage of the wire rope is often caused by the comprehensive accumulation of various factors, which should be judged by the supervisor and decide whether the wire rope is scrapped or continues to be used.

For the damage of the wire rope, the inspector should find out whether the damage of the wire rope is caused by a defect in the mechanism. If so, it is recommended to eliminate the defect before replacing the wire rope.

3.5.1 The nature and quantity of broken wires
The overall lack of juice in the crane does not allow the wire rope to have an infinite life.

For 6-strand and 8-strand wire ropes, wire breakage mainly occurs on the outside. However, it is different for the multi-strand steel wire rope (typical multi-strand structure). Most of the wire breakage of this kind of steel wire rope occurs inside, so it is "invisible" fracture.

Therefore, Table 1 and Table 2 take these factors into consideration. Therefore, when combined with the factors in paragraphs 2.5.2—2.5.11, it is suitable for wire ropes of various structures.

When formulating the scrapping standard for torsion-resistant steel wire ropes, the structure, working hours and use methods of the steel wire rope should be considered. The control standards for the number of interrupted wires of the torsion resistant wire rope on the steel pulley are shown in Table 2.

Special attention should be paid to the local rope segments where the lubricant has dried up or deteriorated.
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