Steel wire rope of the hottest crane and its selec

2022-10-20
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Crane steel wire rope and its selection

steel wire rope is widely used in engineering cranes, which is generally made of many high-strength steel wires. First, a single steel wire is wound together to form a strand, then some of the strands are wound into a rope core, and then the outer strands composed of other strands are wound around the rope core to form a steel wire rope. Some imported steel ropes also contain a plastic insert core, which is usually covered on the rope core in the form of plastic coating after special treatment. Important steel ropes are filled with appropriate lubricant inside the rope to reduce friction

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

the steel wire rope can be divided into straight winding rope and cross winding rope according to the mutual direction of the steel wire wound into strands and strands wound into ropes, and can be divided into left and right same direction twisting and left and right alternating twisting according to the twisting direction of the strands; Generally, the imported steel wire rope takes the cross wound rope as the standard rope, and the rotation direction of the steel wire rope is specified to be consistent with the rotation direction of the outer strand helix based on the longitudinal axis of the steel wire rope with low polishing rate, which is divided into left rotation and right rotation. Accordingly, the rotation direction of the strand is also specified, that is, taking the longitudinal axis of the strand as the benchmark, the direction of the spiral line of the outer wire constituting the strand is the rotation direction of each share. When a single ordinary steel wire rope is used, it rotates in the opposite direction to the steel wire rope. When it is used in the pulley block, it will cause lifting due to the rotation of the steel wire rope. According to the research team of the National University of Singapore, the steel wire rope twists, commonly known as twisting. Compared with ordinary steel wire rope, non rotating steel wire rope has been widely used at present. The so-called non rotating steel wire rope is based on the principle that the direction of the torsional torque of the rope and the strand is opposite and the size is equal: the imported non rotating steel wire rope is different. The principle is to make the rotation direction of the rope core opposite to the rotation direction of the rope itself. When stressed, the torque generated by the rope core is equal to the torque generated by the outer strand, and the direction is opposite

the strand of steel wire rope can also become a compact strand through post-treatment methods such as rolling or die extrusion. After treatment, the diameter of the strand will be reduced and the surface finish will be very high. Therefore, the steel wire rope with tight strands can use thicker steel wires. Under the same diameter, the steel wire rope with tight strands has a higher filling coefficient and a greatly improved breaking force. When multi-layer winding is carried out on the drum, the outer strands of the common wire rope are squeezed seriously between layers, and the surface of the wire rope is worn faster. The tight strand wire rope has high wear resistance and extrusion resistance

the selection of steel wire rope is whether the steel plant's purchase price of scrap steel is still low or not, which directly affects the service life of the rope and causes structural deformation, fracture and accidental failure of the rope. Therefore, the recommended selection principles are as follows:

1) when lifting unguided weights once or lifting unguided weights many times at a large height, choose non rotating steel wire rope

2) ordinary steel wire rope can be used when carrying out a guided weight lifting or multiple guided weight lifting at a small height (such as crane) or when left-hand and right-hand ropes are used in pairs

the determination of the rotation direction of the steel wire rope should follow: the drum with the right-hand rope groove is recommended to use the left-hand steel wire rope; on the contrary, the drum with the left-hand rope groove should use the right-hand steel wire rope

for single-layer wound non rotating steel wire rope, the above principles must be strictly observed, otherwise it is easy to cause permanent deformation of the steel wire rope structure; For multi-layer winding, the rotation direction of the rope is determined by the direction of the drum rope groove, so as to lay a good foundation for the next layer. The friction and extrusion force between the steel wire ropes of the multi-layer winding drum are large, which is easy to cause rope disorder. Therefore, the steel wire rope with a diameter slightly smaller than the rope groove pitch and the rope groove diameter should be selected to increase the contact area between the steel wire rope and the drum, reduce the friction force between adjacent steel wire ropes, and improve the service life of the steel wire rope. Practice has proved that the diameter of steel wire rope is 1% smaller than the pitch of rope groove, which helps to arrange ropes closely and effectively eliminate rope climbing and rope disorder

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, which can well overcome the reverse bending force when the steel wire rope enters and exits the drum for many times, and it is easy to thread the rope. The thicker outer strand, whose steel wire is also thicker, can better resist wear, and the lightweight of replacing steel with plastic has also developed greatly, including mechanical damage, corrosion and extrusion pressure. Therefore, only a good combination of the two advantages is a really high-performance high-quality steel wire rope

in addition, pay attention to the minimum diameter and minimum breaking force of steel wire rope in the selection process, which should comply with the provisions of iso4308 standard

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