Discard of steel wire rope - how and when?

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Inspection of steel wire ropes

Steel wire rope will be worn during use and needs to be inspected regularly.

Daily visual inspection

At least the intended working section of rope for that day shall be observed with the objective of detecting any deterioration of mechanical damage. This shall include the attachment points of the rope to the crane, that the rope spools correctly and runs smoothly over sheaves.

Any noticeable changes shall be reported, and any damage must be inspected by an expert.

Periodic inspection

Steel wire rope shall be inspected at least every 12 months, or more frequently acc. to local legislation by a competent person. Records of such examinations should be maintained.

Steel wire rope on winches and cranes should be inspected regularly acc. to ISO 4309.
Steel wire rope on elevators should be inspected regularly acc. to ISO 4309 and ISO 4344.
Steel wire rope for cableway installations designed to carry persons should be inspected acc. to EN 12927.

Inspection

When inspecting the steel wire, special attention must be paid to the parts of the wire that are empirically exposed to wear and damage.

Wear, broken wires, distortion and corrosion are more common visible signs of deterioration.

Wear is a normal feature of rope service and the correct rope construction ensures that it remains a secondary aspect of deterioration. Correct lubrication of the rope may help reduce outer and inner-wear.

Broken wires are normal features of wire rope service towards the end of the rope's life, resulting from bending fatigue and wear. The local break up of wires may indicate some mechanical fault in the equipment. Correct lubrication in service will increase fatigue performance.

Individual broken wires shall be attended to by removing the wire, see figure.

WARNING! Do not cut the wire, bend it until it breaks close to the inside of the strand. This reduces the risk for ends of wires sticking out of the rope.

Distortions are usually a result of mechanical damage, and if severe, can considerably affect the wire rope strength.

Corrosion of both outer and inner wires indicates insufficient lubrication. Pitting on the external wire surface can result in wire breaks. Inner corrosion occurs in some environments when lubrication is inadequate or of unsuitable type. Reduction in wire rope diameter will frequently guide the observer to this condition, but confirmation can only be made by inner examination of the wire rope.

How to remove broken wires

Steel wire rope discards

Steel wire ropes must be discarded according to current standards for the equipment or the manufacturer's recommendations.
Disposal determination must be performed by a competent person with knowledge of applicable norms and standards.

Warning sign WARNING! Inadequate inspection/disposal can lead to serious injuries.

Typical examples of damage and wear on steel wire ropes


Mechanical damage due to rope movement over sharp edge projection whilst under load.
$Narrow path of wear resulting in fatigue fractures, caused by working in a grossly oversize groove, or over small support rollers.$
Narrow path of wear resulting in fatigue fractures, caused by working in a grossly oversize groove, or over small support rollers.

Severe wear, associated with high tread pressure. Protrusion of fiber main core.

Corrosion of severe degree caused by immersion of rope in chemically treated water.
$Typical wire fractures as a result of bend fatigue.$
Typical wire fractures as a result of bend fatigue.

Break up of the steel core resulting from higt stress application. Note nicking of wires in outer strands.

Typical exampel of localised wear and deformation created at a previously kinked portion of rope.


Localised wear due to abrasion on supporting structure. Vibration of rope between drum and jib head sheave.

Two parallel paths of broken wires indicative of bending through an undersize groove in the sheave.

Severe wear in Langs Lay, caused by abrasion at cross-over points on multi-layer coiling application.

Protrusion of steel core resulting from shock loading.
$Wire fractures at the strand, or core interface, as distict from "crown" fractures, caused by failure of core support.$
Wire fractures at the strand, or core interface, as distict from "crown" fractures, caused by failure of core support.

Strand core protrusion as a result of torsional unbalance created by "drop ball" application (i.e. shock loading).

Multi strand rope "bird caged" due to torsional unbalance. Typical of build up seen at anchorage end of multi-fall crane application.

Discard values for visible broken wires occuring in single-layer and parallel-closed ropes (acc. to ISO 4309-2010)

over a length of 6d and 30d

Rope category number RCN	Total number of load-bearing wires in the outer layer of strands in the rope (a) n	Number of visible broken outer wires (b)
Sections of rope working in steel sheaves and/or spooling on a single-layer drum (wire breaks randomly distributed)	Sections of rope spooling on a multi-layer drum (c)
Classes M1 to M4 or class unknown (d)	All classes
Ordinary lay	Lang lay	Ordinary and Lang lay
Over a length of 6d (e)	Over a length of 30d (e)	Over a length of 6d (e)	Over a length of 30d (e)	Over a length of 6d (e)	Over a length of 30d (e)
1	n ≤ 50	2	4	1	2	4	8
2	51 ≤ n ≤ 75	3	6	2	3	6	12
3	76 ≤ n ≤ 100	4	8	2	4	8	16
4	101 ≤ n ≤ 120	5	10	2	5	10	20
5	121 ≤ n ≤ 140	6	11	3	6	12	22
6	141 ≤ n ≤ 160	6	13	3	6	12	26
7	161 ≤ n ≤ 180	7	14	4	7	14	28
8	181 ≤ n ≤ 200	8	16	4	8	16	32
9	201 ≤ n ≤ 220	9	18	4	9	18	36
10	221 ≤ n ≤ 240	10	19	5	10	20	38
11	241 ≤ n ≤ 260	10	21	5	10	20	42
12	261 ≤ n ≤ 280	11	22	6	11	22	44
13	281 ≤ n ≤ 300	12	24	6	12	24	48
	n > 300	0,04 x n	0,08 x n	0,02 x n	0,04 x n	0,08 x n	0,16 x n

Note: Ropes having outer strands of Seale construction where the number of wires in each strand is 19 or less (e.g. 6x19 Seale) are placed in this table two rows above that row in which the construction would normally be placed based on the number of load bearing wires in the outer layer of strands

(a) For the purposes of this International Standard, filler wires are not regarded as load-bearing wires and are not included in the values of n.
(b) A broken wire has two ends (counted as one wire).
(c) The values apply to deterioration that occurs at the cross-over zones and interference between wraps due to fleet angle effects (and not to those sections of rope which only work in sheaves and do not spool on the drum).
(d) Twice the number of broken wires listed may be applied to ropes on mechanisms whose classification is known to be M5 to M8.
(e) d = nominal diameter of rope.

Discard values for visible broken wires occuring in rotation-resistant steel wire ropes (acc. to ISO 4309-2010)

over a length of 6d and 30d

Rope category number RCN	Total number of load-bearing wires in the outer layer of strands in the rope (a) n	Number of visible broken outer wires (b)
Sections of rope working in steel sheaves and/or spooling on a single-layer drum (wire breaks randomly distributed)	Sections of rope spooling on a multi-layer drum (c)
Over a length of 6d (d)	Over a length of 30d (d)	Over a length of 6d (d)	Over a length of 30d (d)
21	4 strands n ≤ 100	2	4	2	4
22	3 or 4 strands n ≤ 100	2	4	4	8
	At least 11 outer strands
23-1	71 ≤ n ≤ 100	2	4	4	8
23-2	101 ≤ n ≤ 120	3	5	5	10
23-3	121 ≤ n ≤ 140	3	5	6	11
24	141 ≤ n ≤ 160	3	6	6	13
25	161 ≤ n ≤ 180	4	7	7	14
26	181 ≤ n ≤ 200	4	8	8	16
27	201 ≤ n ≤ 220	4	9	9	18
28	221 ≤ n ≤ 240	5	10	10	19
29	241 ≤ n ≤ 260	5	10	10	21
30	261 ≤ n ≤ 280	6	11	11	22
31	281 ≤ n ≤ 300	6	12	12	24
	n > 300	6	12	12	24

Note: Ropes having outer strands of Seale construction where the number of wires in each strand is 19 or less (e.g. 18x9 Seale – WSC) are placed in this table two rows above that row in which the construction would normally be placed based on the number of wires in the outer layer of strands.
(a) For the purposes of this International Standard, filler wires are not regarded as load-bearing wires and are not included in the values of n.
(b) A broken wire has two ends.
(c) The values apply to deterioration that occurs at the cross-over zones and interference between wraps due to fleet angle effects (and not to those sections of rope that only work in sheaves and do not spool on the drum).
(d) d = nominal diameter of rope.