Do you know what you should pay attention to when buying wire rope

In modern practical life, steel wire rope is mostly used as material handling machinery for lifting, traction, tensioning and bearing. The steel wire rope has high strength, light self weight, stable operation, and is not easy to break suddenly. It works reliably. Do you know what to pay attention to when buying wire rope?

1. First of all, from the perspective of packaging, the quality of the steel wire rope is mainly reflected in the following aspects: after the arrival of the steel wire rope, the rope is deformed, broken or scattered, causing the steel wire rope to be rolled, squeezed, scratched or severely rusted without moisture-proof measures, which affects the user. But strictly speaking, it is not limited to this. For example, the packaging does not meet the standards or contract provisions, and the ordering contract does not conform to the delivered goods, etc. are all included in the packaging inspection. The main reasons for the above quality are: the manufacturer did not consider the strength when designing the rope; Not packed according to the packaging standards and contract standards; The transportation department does not load and unload according to the operating procedures; According to Article 78 of Chapter VII of the technical regulations for inspection of steel wire rope for coal mines, if the user and the storage department do not store the steel wire rope in the correct way, 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 of the steel wire rope standard during the twisting of the steel wire rope (refers to the twisting strand or rope), and all kinds of defects are collectively called twisting defects, including: uneven twisting tightness, slack strand, displacement of the rope core, serious uneven tension of the rope strand, uneven tension of the rope strand, bulging, uneven tension of one strand Many strands have different degrees of relaxation and bulging, the outer layer of multi-layer non rotating steel wire rope is loose and bulging, the serious hemp core is displaced, the strand is broken and the wire is bound with iron wire, causing the strand to be loose and disordered, one strand is seriously loose and disordered, there is no hemp core in a length of rope, there are serious wire jumping cases, and the twist distance is uneven...

3. Surface damage: the bruise, bump, hang, scratch or nail on the wire rope or wire surface due to external contact are collectively referred to as surface damage. However, the plastic deformation caused by the wire pressing die, preformer or roller die during the manufacturing process does not belong to the category 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 (local or overall) of steel wire rope. Causes of rust (floating rust) on the surface of new steel wire rope:

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

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

Third, the steel wire rope is poorly oiled in production,

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

Slight floating rust is allowed on new ropes (especially the steel wire ropes that are not coated with oil as required by the user), but the manufacturer shall be held responsible if there are still rust spots or pits and pits after wiping.

5. Galvanizing defects: cracks, falling off, zinc accumulation, zinc scar and exposed steel on the surface of galvanized steel wire rope belong to galvanizing defects.

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

6. Poor oiling refers to the lack and unevenness of impregnating agent and lubricant of 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 surface of the steel wire rope that is not coated with lubricant." This is also a measure to improve the quality of wire rope.

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

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

For example, when the steel wire rope passes through the heating oil tank during twisting, the parking time is long, the oil temperature is too high, the oil evaporates or the oil is missed, etc. will cause bad oil coating. If this phenomenon is found, measures shall be taken in time to protect it.

7. Hemp core exposed

The phenomenon that the hemp core is extruded from the whole length of the steel wire rope or the gaps between the partial strands is called the hemp core exposure.

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

Under normal conditions, there should be a small gap between each strand of the whole length of the steel wire rope, or a small amount of hemp batt flying out of the gap. However, if the use of the steel wire rope is affected by the too thick joint or the disconnection of the joint, a claim should be filed with the manufacturer.

8. Loose strands

After the end of the wire rope is loosened and cut, the strand or the wire in the strand (all or part) is loosened and does not form.

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

9. Poor connector

The steel wire in the wire rope is excessively large 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 in the process of wire drawing, strand twisting or rope closing. The serious problem is that some steel wire rope manufacturers

Poor joint sometimes causes the strand diameter to increase, and sometimes forces the adjacent steel wire to dislocation, and the welding head is thick and protruding, making the strand rope surface not smooth. According to the standard, the steel wire rope of 18mm in general thin steel wire rope shall not be more than 4 places within 1000m, and the steel wire rope for important purposes or fixed length steel wire rope is not allowed.

10. Strand relaxation (twisted fried dough twist)

The phenomenon of protrusion or collapse of individual strands in the wire rope often occurs at the same time as the loosening of strands.

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 unstable operation of equipment.

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