Elevator wire rope scrapping standard - Solutions - Huaqiang Electronic Network

SMD aluminum electrolytic capacitor

Brand AVX TPSE226M035R0125 Low impedance tantalum capacitor AVX 22

Electronic scale crystal oscillator 3.2*2.5mm 3225 16M (16.000MHZ) 12PF 10PPM 20PPM 30PPM

Huaqiang Square crystal original spot stock

Wire rope scrapping standard: "Practical specification for inspection and scrapping of wire rope for lifting machinery" (GB5972-86)
1. The nature and number of broken wires The overall design of the hoisting machine does not allow the wire rope to have an infinitely long life.
For 6- and 8-strand wire ropes, the broken wire mainly occurs on the outside. The wire ropes (typically multi-stranded structures) of the multi-layer strands are different. Most of these wire rope breaks occur internally and are therefore "invisible" fractures.
The following table considers these factors, so it is applicable to wire ropes of various constructions when considered in combination with the factors in paragraphs 2.5.2 to 2.5.11.
2. Broken wire at the end of the rope When the broken wire is broken at or near the rope end, even if the number is small, it indicates that the stress is high in the part, which may be caused by incorrect installation of the rope end, and the cause of the damage should be ascertained. If the length of the rope is allowed, the part of the broken wire should be gathered. 3. The local part of the broken wire should be scrapped if the broken wire is close together to form a local gathering. If the broken wire gathers within the rope length of less than 6d, or is concentrated in any of the strands, the wire rope should be scrapped even if the number of broken wires is less than the value listed.
4. Increase rate of broken wire In some occasions, fatigue is the main cause of wire rope damage. Broken wire starts to appear after a period of use, but the number of broken wires increases gradually, and the time interval is shorter and shorter. In this case, in order to determine the rate of increase of the broken wire, the increase in broken wire should be carefully checked and recorded. It was found that this "law" can be used to determine the date of future scrapping of the wire rope.
5. Strand break If the entire strand breaks, the wire rope should be scrapped.
6. Reduction of rope diameter due to damage of the rope core When the fiber core of the steel rope is damaged or the steel core (or internal strands in the multilayer structure) is broken to cause a significant decrease in the rope diameter, the steel rope should be scrapped.
Minor damage, especially when the stresses in all strands are well balanced, may not be apparent with the usual test methods. However, this situation can cause the strength of the wire rope to be greatly reduced. Therefore, when there are any signs of internal minor damage, the inside of the wire rope should be inspected for identification. Once the damage is confirmed, the wire rope should be scrapped.
7. Reduction of elasticity In some cases (usually related to the working environment), the elasticity of the wire rope is significantly reduced and it is unsafe to continue using it.
The reduction in the elasticity of the wire rope is difficult to detect. If the inspector has any doubts, the wire rope expert should be consulted. However, the reduction in elasticity is usually accompanied by the following phenomena:
a. the rope diameter is reduced;
b. elongation of the wire rope pitch;
c. Since the parts are pressed against each other, there is a gap between the wires and between the strands;
d. A fine brown powder appears in the recess of the strand;
e. Although no broken wires were found, the wire ropes were significantly less susceptible to bending and the diameter reduction was much faster than simply due to wire wear. This situation can lead to sudden breakage under dynamic load, so it should be immediately scrapped.
8. Two cases of external and internal wear and tear:
a. Internal wear and crater This condition is caused by friction between the individual strands in the rope and the steel wire, especially when the wire rope is subjected to bending.
b. External wear The wear of the wire surface of the outer strand of the wire rope is caused by the frictional contact between the pulley and the rope groove of the drum under pressure. This phenomenon is particularly noticeable when the wire rope is in contact with the pulley during the acceleration and deceleration movement, and the outer wire is ground into a flat shape.
Insufficient lubrication, or incorrect lubrication, and the presence of dust and sand can exacerbate wear.
The wear reduces the sectional area of ​​the wire rope and thus the strength. When the outer wire is worn to 40% of its diameter, the wire rope should be scrapped.
When the diameter of the wire rope is reduced by 7% or more with respect to the nominal diameter, the wire rope should be scrapped even if no broken wire is found.
9. External and internal corrosion corrosion is particularly prone to occur in marine or industrially polluted atmospheres. It not only reduces the metal area of ​​the wire rope, but also reduces the breaking strength, and will also cause the surface to be rough and develop cracks from it to accelerate fatigue. Severe corrosion can also cause a decrease in the elasticity of the wire rope.
9.1 External Corrosion The corrosion of the external steel wire can be observed with the naked eye. When there is a deep pit on the surface, the wire should be scrapped when it is quite slack.
9.2 Internal Corrosion Internal corrosion is more difficult to detect than external corrosion that often occurs with it. However, the following phenomena are available for identification:
a. Change in wire rope diameter. The diameter of the wire rope is usually small at the bend of the winding around the pulley. However, for the wire rope of the stationary section, the diameter of the wire rope is often increased due to the rust accumulation of the outer strand.
b. The gap between the outer strands of the wire rope is reduced, and often accompanied by broken wires between the outer strands.
If there is any indication of internal corrosion, the wire rope should be internally inspected by the supervisor. If serious internal corrosion is confirmed, the wire rope should be immediately scrapped.
10. The deformed wire rope loses its normal shape and produces a visible deformity called "deformation". This deformation (or deformed part) may cause a change, which may result in uneven stress distribution inside the wire rope.
The deformation of the wire rope is distinguished from the appearance, and can be divided into the following types:
10.1 The wavy wavy deformation is that the longitudinal axis of the wire rope is in the shape of a spiral. This deformation does not necessarily result in any loss of strength, but if the deformation is severe, it will cause an impulsive transmission caused by the beating. Long time will cause wear and broken wires.
When the wave shape appears, if the length of the wire rope does not exceed 25d, if d1≥4d/3, the wire rope should be scrapped.
Where d is the nominal diameter of the wire rope; d1 is the diameter of the envelope after deformation of the wire rope.
10.2 Cage Distortion This deformation occurs on steel wire ropes with steel cores. This deformation occurs when the outer strands are disjointed or become longer than the inner strands. Cage-distorted wire ropes should be scrapped immediately.
10.3 Strand Extrusion This condition is usually accompanied by cage distortion. The strands are squeezed out to indicate that the wire rope is unbalanced. The wire rope extruded from the strands should be immediately scrapped.
10.4 Wire extrusion This deformation is a part of the wire or wire bundle arched on the side of the wire rope carrying the pulley groove to form a ring. This deformation is often caused by an impact load. If such deformation is severe, the wire rope should be scrapped.
10.5 Local increase in rope diameter The diameter of the wire rope may increase locally and may affect a relatively long length of wire rope. The increase in rope diameter is usually related to the distortion of the core (for example, in a special environment, the fiber core expands due to moisture), and the inevitable result is that the outer strands are unbalanced and the positioning is incorrect.
Wire ropes with a severely increased rope diameter should be scrapped.
10.6 Kink and kink is a deformation caused by the wire rope being looped in the event that it is impossible to rotate around its axis. The result is an uneven wear and tear that causes extra wear and tear. In severe cases, the wire rope will be distorted, leaving only a very small portion of the wire rope strength.
Severely twisted wire ropes should be scrapped immediately.
10.7 Local reduction in rope diameter Local reduction in wire rope diameter is often associated with breakage of the rope core. Special inspection should be carried out to see if there is such a deformation at the end of the rope.
Wire ropes with a severely reduced rope diameter should be scrapped.
10.8 Part of the flattened wire rope is flattened due to mechanical accidents. In severe cases, the wire rope should be scrapped. #p#分页头#e#
10.9 Bending and bending is the angular deformation caused by the wire rope under the influence of the outside world.
This deformed wire rope should be scrapped immediately.
11. Damage to the wire rope due to the action of heat or arc The wire rope shall be scrapped when it is subjected to special heat and its appearance has a recognizable color.