Some introduction of wire rope？

2023-04-12 22:12:13

The Steel Wire Rope has the characteristics of the same section, high strength, high elasticity, good toughness, wear resistance, stable operation at high speed and can withstand impact loads. Wire ropes generally have signs such as broken wires and broken strands before breaking, which is easy to inspect and easy to prevent accidents. Therefore, it is widely used in lifting operations and is the main rope in hoisting. It can be used for lifting, traction, bundling, etc.

1. The structure and type of wire rope

According to the twisting method, Steel Wire ropes are divided into three types: single-wound, double-wound and triple-wound wire ropes. Among them, the double-wound steel wire rope has a large number of wires, high flexibility, and is easy to be wound on pulleys and drums, so it is generally used in lifting operations. It is a double-wound wire rope.

According to the twisting direction, double-wound steel wire ropes are divided into co-rotation, alternating twist and mixed twist. In the steel wire rope, the twisting direction of the steel wire and the twisting direction of the Steel Wire Strands are the same as the same direction twist (slow twist). Coaxially twisted wire ropes are softer, have a flat surface, and have a relatively large contact surface with the pulley. Therefore, the wear and tear is light, but it is easy to loosen and kink and curl, and it is easy to rotate when hoisting. Alternately twisted (reverse-twisted) wire rope, the twisting direction of the steel wire is opposite to the twisting direction of the steel strands. The alternately twisted wire rope has high strength and small tendency to twist and curl, and is widely used in hoisting. The twisting method of the two adjacent strands of the mixed-twist steel rope is opposite, that is, half forward twist and half reverse twist. The performance of the mixed-strand steel wire rope is better, but it is troublesome to manufacture and the cost is high, and it is rarely used under normal circumstances.

According to the number of strands and the number of wires in one strand, steel wire ropes can be divided into 6 strands of 19 wires, 6 strands of 37 wires, and 6 strands of 61 wires. In the case of the same diameter of the wire rope, the more the number of wires in the strand, the thinner the diameter of the wire, the softer the wire, and the greater the flexibility.

the better. However, the wire ropes twisted with thin steel wires are not as wear-resistant as those made with thicker steel wires.

According to different rope cores, steel wire ropes can be divided into three types: hemp core (cotton core), asbestos core and metal core. The steel wire rope with oil-impregnated hemp or cotton yarn as the core is relatively soft and easy to bend. At the same time, the rope core soaked in oil can lubricate the steel wire, prevent the steel wire from rusting, and reduce the friction between the steel wires, but it cannot be subjected to heavy pressure and Work at higher temperatures.

2. Measuring method of wire rope diameter

Wire rope diameter should be measured with a vernier caliper with wide jaws wide enough to span two adjacent strands.

The measurement should be carried out on a straight line 15 m away from the end of the wire rope without tension, on two sections at least 1 m apart, and two values are measured at the same section perpendicular to each other. Use the average value of the four measurement results as the measured diameter of the wire rope. The ratio of the difference between the measurement results of the same section and the measured diameter is the out-of-roundness, and the out-of-roundness of the wire rope should not be greater than 4% of the nominal diameter of the wire rope.

3. Safe use and management of wire rope

In order to ensure the safety of the wire rope, the following points must be done in the selection, operation and maintenance:

The selection of steel wire ropes should be reasonable, and overloading is not allowed.

Before cutting the wire rope, it should be bundled with thin steel wire at the incision to prevent the rope end from loosening after cutting. When cutting the wire rope, prevent the wire scraps from flying and damaging the eyes.

Before using the wire rope, the wire rope must be inspected in detail, and those that meet the scrapping standard should be scrapped and renewed, and it is strictly prohibited to use.

There should be no rupture on the edge of the pulley that wears the wire rope. Where the wire rope is in direct contact with the sharp corners of objects, equipment or objects in contact, a guard plate or a wooden board should be placed to prevent damage to the wire rope.

It is necessary to prevent the wire rope from contacting with wires and cables to avoid arc damage to the wire rope or electric shock accidents.

When the wire rope is wound on the reel, it should be arranged tightly and neatly one by one, and should not be overlapped or separated from the seam.

4. Scrap of wire rope

The steel wire rope will be constantly worn, bent, deformed, corroded and broken during use, and should be scrapped when it cannot meet the safety requirements to avoid danger. Crane wire rope maintenance, maintenance, installation, inspection and scrapping (GB/T 5972) stipulates that the wire rope should be scrapped when it reaches the following conditions:

When the broken wire of the wire rope reaches the specified value.

The wear and corrosion of the wire rope diameter is greater than 7% of the wire rope diameter.

The wear of the outer steel wire reaches 40% of the steel wire.

The whole strand of the wire rope is broken.

Burned by high temperature such as arc.

The wire rope produces the following plastic deformation:

1) Wavy.

2) Cage distortion.

3) The strands are extruded.

4) Steel wire extrusion.

5) The rope diameter increases or decreases locally.

6) Partially squashed.

7) Severely kinked.

8) Severely bent.