Wire rope is one of the indispensable parts in the construction of rotary drilling rigs. The working conditions of wire rope are complex and changeable. In many cases, wire rope will be scrapped early. The following are the main points about the use of wire rope. I hope everyone can make good use of the rope and get great benefits. Next, the editor of Xianji.com will introduce the classification, precautions, lubrication maintenance and wear of wire rope.

Classification of wire rope

1. According to the cross-sectional shape of wire rope: there are round wire rope and flat wire rope.

2. According to the cross-sectional shape of wire rope strand: there are round strand and special-shaped strand, which can be divided into: triangular strand, flat strand, etc.

3. According to the state of contact between each layer of wire rope in the wire rope strand: point contact wire rope, line contact wire rope (including point and line contact wire rope).

4. According to the cross-sectional shape of wire rope, it is divided into: wire rope made of round wire and wire rope made of special-shaped wire (such as sealed wire rope).

5. According to the number of strands, the wire rope can be divided into: single strand, six strands, eight strands, twelve strands, eighteen strands, thirty-four strands, etc.; the first three types of wire ropes are composed of one layer of strands; twelve strands and eighteen strands are composed of two layers of strands; and thirty-four strands are also called non-rotating wire ropes.

6. According to the twisting direction and twisting method of the wire rope: According to the twisting direction of the strands, right-hand twist and left-hand twist; According to the twisting method of the wire rope, alternate twist (reverse twist) and same-direction twist (forward twist).

7. According to strength: According to the nominal strength of the single wire, the wire rope is divided into several grades. The grading standards of different countries are different. For example, my country divides round strands.

Precautions for wire ropes

1. When unwinding and installing the wire rope, the correct method should be used to prevent the wire rope from kinking. In addition, be careful not to let the surface of the wire rope get stained with sand to avoid aggravating wear and affecting the service life of the wire rope.

2. If the whole roll of wire rope needs to be cut off during use, the end should be tied or melted according to Figure 3 or Figure 4.

3. When the rope clamp must be installed, it should be fixed according to the method in Figure 5. The spacing between the rope clamps is 5-6 times the diameter of the wire rope.

4. The twist direction of the wire rope should be selected so that the winding method of the wire rope at the bottom layer of the drum conforms to Figure 6.

5. When the wire rope is wound on the drum, it should be arranged neatly and not wound randomly, otherwise it will cause serious squeezing and crushing of the wire rope during work, affecting the service life of the wire rope.

6. The new rope must be "run-in" under light load at the beginning of use. This can increase the service life of the wire rope. Excessive impact loads should also be avoided during use to damage the wire rope.

7. Pay special attention to accurately calculate the distance during the drilling process, and do not release the rope excessively to prevent the wire rope from being wound in a relaxed state, which may cause structural damage and make the entire wire rope scrapped.

8. For multi-layer winding equipment, it is inevitable that the wire rope will "bite the rope" during use. It is recommended to check the "bite the rope" part frequently during use, and strengthen lubrication, or regularly "slip the rope" and cut it off to stagger the "bite the rope" part.

9. After the wire rope is put into use, the performance will gradually decrease. Therefore, after a period of use, the new rope should be frequently checked for parts of the wire rope that are prone to damage, such as the part where the wire rope "bites the rope", the wire rope under the drum, the wire rope passing through the pulley when a severe impact occurs, and the wire rope entering and exiting the drum, etc., to provide a basis for the reasonable and safe use of the wire rope through regular inspections.

10. Broken wire processing

When the wire rope is broken and still needs to be used, the broken wire should be processed in time. You can use wire cutters to clamp the head of the broken wire and bend it back and forth repeatedly until the wire breaks. After this treatment, the broken wire head will be clamped between the strands and will not cause harm to the use of the wire rope. When the number of broken wires in one lay reaches 10% of the total number of outer wires, the wire rope must be replaced.

11. Suggestions

Since the working mode of the wire rope of the rotary drilling rig belongs to single-rope lifting, that is, the wire rope has a free rotating end during work, based on safety and convenience of operation, anti-rotation wire rope should be used first when purchasing wire rope.

Lubrication and maintenance of wire ropes

1. Wear and tear during the use of wire ropes

Continuous wear and adhesive wear occur at the actual contact and friction parts; abrasive wear is caused by the adhesion and mixing of dust and abrasives; if the wire rope is exposed to a humid, acidic, or alkaline gas environment, it will cause corrosion and chemical erosion; due to overloading, impact, or excessive bending, the steel wire structure changes and the strength decreases, resulting in fatigue, which is a form of damage that is not easy to detect but gradually accumulates and suddenly occurs.

Due to the excessive pressure between the steel wires, the steel wire and the rope wheel, and the drum wheel, the oil film strength is insufficient, resulting in marks and deformation. Wear caused by friction heat caused by direct contact with metal.

2. Lubrication and maintenance

(1) Lubricating oil filling method. When soaking, first clean the dirt, dust, oil mud, etc. in the gaps between the wire rope strands with superheated steam or compressed air and a steel brush, and then put it in an oil bath for immersion. The oil used should be heated to about 50°C for penetration. The interval for immersion is once every three months at normal temperature. You can also use a portable oiler with an oil brush or a special oiler. The former is used for short wire ropes. The lubrication interval is about once every five days, and once every three days under dusty, high temperature or open air conditions.

(2) Grease filling method. The ideal method for filling lubricant is to add lubricant to the place where the wire rope tends to open when it passes through the rope wheel or drum. The lubricant can be added manually or mechanically.

Wire rope wear

During operation, the wire rope contacts other objects and has relative motion, generating friction. Under the action of mechanical, physical and chemical factors, the surface of the wire rope is constantly worn. Wear is the most common damage mode of wire rope, which is generally divided into three types: external wear, deformation wear and internal wear: the typical cross-sectional shape of the worn wire, namely external uniform wear, deformation wear and internal wear.

1. External wear The wear caused by the contact between the outer periphery of the wire rope and the surface of objects such as the pulley groove, drum wall, hook head, etc. during use belongs to external wear. After external wear, the diameter of the wire rope will become thinner, and the thin steel wire on the outer surface will be worn flat. The external wear of the wire rope reduces the cross-sectional area of ​​the steel wire that bears the load, and the breaking load of the wire rope is also reduced accordingly. Through experiments, it is found that single-circle wear is worse than full-circle wear, so the steel wire with single-circle wear should be changed to full-circle uniform wear as much as possible.

2. Deformation wear The surface damage of the wire rope caused by vibration and collision is called deformation wear. This is a local wear phenomenon. For example, the steel wire rope on the surface of the drum is hit by other objects, the lifting steel wire rope of the crane is entangled with each other, or the bite phenomenon caused by the deviation of the pulley and the center of the drum will cause deformation wear of the wire rope. If the fine steel wire on the worn surface is cut open, the deformation wear and external wear are deformed due to local extrusion, and the cross-section of the steel wire stretches to both sides at the extrusion into a wing shape. From the outside, the width of the steel wire is expanded. Although the cross-sectional area of ​​the steel wire rope is not reduced much, the surface material of the steel wire at the local extrusion is hardened, which is very easy to break.

3. Internal wear During use, the entire load borne by the wire rope when passing through the drum or pulley is pressed on one side of the wire rope, and the radius of curvature of each thin steel wire cannot be exactly the same. At the same time, due to the bending of the wire rope, the thin steel wires inside the wire rope will exert force on each other and slip. At this time, the contact stress between the strands increases, causing the steel wires between adjacent strands to have local indentations and deep concave. When repeatedly stretched and bent, stress concentration occurs at the deep concave and the wire is broken, forming internal wear. Usually, the pressure on the surface of the thin steel wire is proportional to the pressure of the wire rope. Under the same tension, the pressure per unit area is different due to different pressure areas. From the perspective of surface pressure wear, it is more advantageous to use line contact wire rope than point contact wire rope, and it is more advantageous to use surface contact wire rope than line contact wire rope. In addition, the bending degree and movement speed of the wire rope have an impact on the internal wear of the wire rope. Obviously, choosing line contact or surface contact type wire rope is an effective way to reduce internal wear.

The above is the classification, precautions, lubrication and maintenance, and wear of wire ropes introduced by Xianji.com. Wire ropes are widely used in industry. Because of their strong toughness and bendability, they are loved by workers. Most lifting machines need to use wire ropes. And they have a long service life and are not easy to break, which is why they are widely used.