How to buy wire rope? What should I pay attention to when buying wire rope?

In modern real life, steel wire rope is mostly used in material handling machinery for lifting, traction, tension and bearing. The steel wire rope has high strength, light weight, stable operation, not easy to break suddenly, and reliable operation. Do you know what to pay attention to when buying steel wire rope?

1. first of all, from the packaging point of view, the quality of the steel wire rope is mainly reflected in that after the arrival of the steel wire rope, the rope is deformed, broken or scattered, which causes the steel wire rope to be rolled, crushed, scratched or seriously rusted without moisture-proof measures and affects the users. But strictly speaking, it does not stop there. For example, the packaging does not conform to the standards or the contract provisions, and the order contract does not conform to the delivered physical objects are all within the scope of packaging inspection. The main reasons for the above quality are: the manufacturer did not consider the strength when designing the rope; Not packed in accordance with the packaging standards and contract standards; The transportation department does not load and unload according to the operating procedures; The use and storage department does not store the steel wire rope in the correct way. According to Article 78 in Chapter VII of the technical specification for inspection of steel wire rope for coal mine, if any one of the provisions is violated in the acceptance inspection, the responsibility must be investigated.

2. twisting defect, the so-called twisting defect, in a broad sense, refers to all kinds of defects that do not meet the twisting quality requirements in the steel wire rope standard during the twisting process (referring to the twisting strand or rope), which are collectively referred to as twisting defects, including: uneven twisting tightness, loose strand core displacement, serious uneven rope strand tightness, uneven rope strand tightness bulge, one strand bulges due to uneven tightness Many strands have different degrees of relaxation and bulge, the outer strands of multi-layer non rotating steel wire rope are loosened and bulged, the hemp core is seriously displaced, the strands are bound with iron wire after the strands are broken, resulting in the relaxation and confusion of strands, cases of serious relaxation and confusion of one strand, cases of serious wire skipping, cases of serious uneven lay distance, etc...

3. surface damage: the bruises, bumps, hangs, scratches or nails on the steel wire rope or steel wire surface due to external contact are collectively referred to as surface damage, but the plastic deformation caused by the wire pressing die, pre deformer or roller die during the manufacturing process does not belong to the scope of surface damage. If any of the following conditions is found during the inspection, the responsibility shall be investigated according to the standard.

4. surface rust (floating rust) and oxidation on the surface of steel wire rope (local or overall). Causes of rust (floating rust) on the surface of new steel wire rope:

First, acid, alkali, salt and other substances remain on the steel wire surface during production,

Second, the steel rope grease contains too much acid, alkali or moisture,

Third, the steel wire rope was poorly oiled during production,

Fourth, improper moisture-proof measures for packaging (due to the long-distance transportation of imported steel wire rope) and harmful gas impregnation.

Slight floating rust is allowed for new ropes (especially steel ropes not coated with oil as required by the user), but the manufacturer shall be investigated for responsibility if there are still rust spots or pits or pitted surfaces after wiping.

5. galvanizing defects: cracks, falling off, zinc accumulation, zinc scar and steel exposure on the surface of galvanized steel wire rope are all galvanizing defects.

The main causes of galvanizing defects are that the oil stain or oxide skin on the surface of galvanized steel wire is not washed off, and the galvanizing process is not strictly controlled, such as the purity of zinc solution, temperature, equipment operation speed and stability, improper treatment of zinc slag, etc.

6. poor oiling refers to the lack and unevenness of impregnant and lubricant for steel wire or hemp core on the surface of steel wire rope.

The steel wire rope standard stipulates: "unless otherwise required by the user, there shall be no place in the steel wire rope where the steel wire surface is not coated with lubricant." This is also a measure to improve the quality of steel wire rope.

Generally, there are two kinds of steel wire rope oil used by steel wire rope manufacturers: one is hemp core grease (impregnating agent) and the other is coating agent (surface grease).

The main reasons for bad oiling are as follows: first, the quality of domestic grease is not up to standard, but the way of dipping and oiling is improper.

For example, when the steel wire rope passes through the heated oil tank during rope twisting, long shutdown time, high oil temperature, grease evaporation or missing coating will all cause bad oil coating. If this phenomenon is found, measures shall be taken in time to protect it.

7. exposed hemp core

The hemp core is exposed when it is extruded from the full length of the steel wire rope or the gap between the strands in part.

The reasons for hemp core exposure are: uneven thickness of hemp core, local enlargement or disconnection due to poor hemp core joint, and uneven twisting of rope strands.

Under normal circumstances, there should be a small gap between the strands of the full length of the steel wire rope, or a small amount of oakum flying out of the gap is a normal phenomenon. However, if the use of the steel wire rope is affected due to the too thick joint or the disconnection of the joint, a claim should be made to the manufacturer.

8. loose strands

After the end of the steel wire rope is loosened and cut off, the strand or the steel wire in the strand (in whole or in part) is loosened and will not form.

The loose strands of steel wire rope are mainly caused by improper treatment of pre deformation and post deformation process in manufacturing.

9. poor connector

The steel wire in the steel wire rope is too large locally due to improper joint method, incorrect joint center or poor welding.

The main reason for the poor joint is that the steel wire is broken and poorly welded during the process of wire drawing, stranding or rope closing. Some steel wire rope manufacturers are serious

Poor joints sometimes cause the strand diameter to increase, sometimes force the adjacent steel wires to dislocation, and the welding head is thick and protruding, making the strand rope surface not smooth. According to the provisions of the standard, there shall be no more than four 18mm thin steel wire ropes within 1000 meters, and steel wire ropes for important purposes or fixed length steel wire ropes are not allowed.

10. strand relaxation (twisted fried dough twist)

Individual strands in the steel wire rope protrude or fall, which often occurs at the same time as the strands become loose.

The causes of these defects are: uneven thickness of hemp core, incorrect position of wire pressing pad, improper control of pre deformation fixture, inconsistent bending depth of each strand or uneven operation of equipment.

This phenomenon is not allowed, but if it occurs at the end of the steel wire rope and does not affect the order length, it can be handled through negotiation. If it has affected the use, a claim shall be made.