Selection Rules For Purchasing Steel Wire Ropes For Cranes

Selection Rules For Purchasing steel Wire Ropes For Cranes
 

Steel wire ropes are commonly used in construction cranes and are generally made of many high-strength steel wires.
 

It first consists of single steel wires wound together to form strands, then some of the strands are wound into a rope core, and the outer strands composed of other strands are wound around the core to form a wire rope.
 

Some steel wire ropes also contain a plastic ferrule inside, usually in the form of a plastic coating that is specially treated to cover the rope core, and important steel wire ropes are filled with appropriate lubricants inside the rope to reduce friction.
 

Steel wire ropes are generally divided into three types according to the rope core material: organic matter (hemp core and cotton core), asbestos core or metal core, and there is usually no filler or lubricant inside the rope.
 

Steel wire rope can be divided into forward winding rope and cross winding rope according to the mutual direction of steel wire winding into strands and strands into ropes, and according to the twist direction of the strands, it can be divided into left and right laying in the same direction and left and right alternating laying;
 

Ordinary steel wire ropes tend to rotate in the opposite direction to the wire rope when they are used alone. When used in a pulley block, the rotation of the wire rope will cause the hoisting wire rope to twist, commonly known as twisting.
 

Compared with ordinary steel wire ropes, non-rotating steel wire ropes have begun to be widely used.
 

The so-called non-rotating steel wire rope is based on the principle that the torsional moment of the rope and the strands is in the opposite direction but equal in magnitude; the imported non-rotating steel wire rope is different, and the principle is to make the rotation direction of the rope core opposite to that of the rope itself. When stressed, the torque produced by the rope core is equal in magnitude to that produced by the outer strands, but opposite in direction.
 

The strands of the steel wire rope can also be made into compact strands by post-processing methods such as rolling or die extrusion. After treatment, the diameter of the strands will be reduced, and the surface finish will be very high.
 

Therefore, the steel wire rope with compact strands can use thicker steel wires. Under the same diameter, the steel wire rope with dense strands has a higher filling coefficient and the breaking force is greatly improved.
 

When multi-layer winding is carried out on the reel, the outer strands of the common-strand steel wire rope are more severely squeezed between layers, and the surface of the steel wire rope wears faster. The tight-strand steel wire rope has higher wear resistance and extrusion resistance.
 

Whether the selection of steel wire rope is correct or not will directly affect the service life of the rope and cause structural deformation, breakage and accidental failure of the rope. Therefore, the recommended selection principles are as follows:
 

1. When carrying out a non-guided heavy lifting or multiple unguided heavy lifting at a large height, use a non-rotating wire rope;
 

2. Ordinary steel wire ropes can be used when carrying out one lift with a guide weight or multiple lifts with a guide weight at a small height (such as driving) or using left-handed and right-handed ropes in pairs.
 

The direction of rotation of the wire rope should be determined as follows: left-handed steel wire rope is recommended for right-handed rope groove drums; on the contrary, right-handed steel wire ropes should be used for left-handed rope groove drums.
 

For non-rotating steel wire ropes wound in a single layer, the above principles must be strictly followed, otherwise it will easily cause permanent deformation of the wire rope structure; good foundation.
 

The friction between the steel wire ropes and the extrusion force of the multi-layer winding drum are relatively large, which is easy to cause rope disorder. Therefore, the steel wire rope with a diameter slightly smaller than the pitch of the rope groove and the diameter of the rope groove should be selected to increase the distance between the wire rope and the drum. The contact area between them reduces the friction between adjacent steel wire ropes, thereby improving the life of the steel wire ropes. Practice has proved that the diameter of the steel wire rope is 1% smaller than the pitch of the rope groove, which helps to arrange the rope tightly and effectively eliminate the phenomenon of rope climbing and rope chaos.
 

Under the same diameter, the more the number of outer strands of the steel wire rope, the thinner the diameter, and the thinner the single steel wire. This kind of steel wire rope has good flexibility and can well overcome the reverse bending force when the steel wire rope enters and exits the drum for many times. , It is also easy to thread the rope.
 

The thicker outer strands, with their thicker wires, are better able to resist abrasion, mechanical damage, corrosion and crushing forces. Therefore, only a good combination of the two advantages can be a high-quality steel wire rope with real high performance.
 

In addition, during the selection process of the steel wire rope, it is necessary to pay attention to its minimum diameter and minimum breaking force, which should meet the requirements of the standard.