types of wire rope breaks factory

Industrial machines generally have heavy loads to lift and pull. Whether it’s excavators or farm machinery, wire rope is the rope that is used. Industrial wire ropes typically range from 3/8” (9.5mm) to 2-1/2” (63.5mm) in diameter, and besides heavy machining applications, wire ropes also serve as support cables for large static structures such as stadium roofs and bridges. Manufacturing a wire rope begins with steel wire that is anywhere from .6 to 8 millimeters in diameter. The first step is to wind several of these wires together, into a strand. How many wires per strand depends on the application of the wire. Different applications require various levels of flexibility and strength.

Steel wires are used for wire ropes and are typically fashioned from a non-alloy carbon steel material. This metal has a carbon content of 0.5 to 0.95%, which makes it incredibly strong. As a result of its strength and durability, steel wires are able to support large tensile forces and can run over sheaves with small diameters.

Strands are created when wires of different layers cross each other. Parallel lay strands are some of the most commonly manufactured strands. The lay length of the wire strands is generally equal to the wires of any two layers that are parallel. This means that there is linear contact. Inner layer wires support the outer layer wires along the entire length of the strand.

In essence, spiral ropes are round strands that are assembled in layers of wires that are aligned in a spiral design. Spiral ropes are constructed so that they are non-rotating, which means that that there is practically no tension under the rope torque.

Stranded ropes are comprised of several different layers of strand that are laid in multiple spiraling layers around a core. A stranded rope core can come in three different types: fiber cores, wire strand cores, or independent wire rope cores. Fiber cores are the most flexible and elastic of the 3 variations, but are easily crushed. Wire strand cores are typically used for suspension and have a high tensile strength. Independent wire rope is the most durable in all types of environments.

GENERAL NOTE: Broken wire rope-removal criteria cited in B30.30 apply to wire rope operating on steel sheaves and cast iron sheaves and drums and wire rope operating on multilayer drums, regardless of sheave material. When drum spooling is single layer, synthetic or sheaves with synthetic linings should not be used because there are no broken wire criteria for this configuration, and internal wire breaks may occur in large numbers before any break or signs of substantial wear are visible on the outside wires of the rope.

1) If one valley break is detected, sections of rope 30 x nominal diameter in length on both sides of the detected valley break should be inspected over a bend. For additional information see ASME B30.30-2019, figure 30-0.2-7.

A finished wire rope is comprised of individual wires, make up individual strands, which are then laid in a helical pattern around a synthetic or steel core.

Wires are the smallest component of wire rope and they make up the individual strands in the rope. Wires can be made from a variety of metal materials including steel, iron, stainless steel, monel, and bronze. The wires can be manufactured in a variety of grades that relate to the strength, resistance to wear, fatigue resistance, corrosion resistance, and curve of the wire rope. Selecting the proper wire rope for your application is essential to long-lasting performance in a wire rope.

Strands of wire rope consist of two or more wires arranged and twisted in a specific arrangement. The individual strands are then laid in a helical pattern around the core of the rope. Strands made of larger diameter wires are more resistant to abrasion, while strands made of smaller diameter wires are more flexible.

The core of a wire rope runs through the center of the rope and supports the strands and helps to maintain their relative position under loading and bending stresses. Cores can be made from a number of different materials including natural or synthetic fibers and steel.

Lubrication is applied during the manufacturing process and penetrates all the way to the core. Wire rope lubrication has two primary benefits:Reduces friction as the individual wires and strands move over each other,

Wire ropes are largely used in marine environment or for rigging purposes. They receive considerable loads and thus suffer a great deal of mechanical damage throughout their service life. Moreover, research has shown that the major cause of wire rope failure is excessive deterioration and corrosion, lack of maintenance and inspection, and wrong usage resulting in early discarding, reduced safety and replacement cost increase.

Sometimes damage can be easily detected, while in other cases fractured wires may occur on the inside. Hence, wire ropes should be inspected and maintained by the right person (competent person assigned by the company), to assure they’re in perfect condition. Regular inspectionsensure high rope performance, long service lifetime , safety of personnel and equipment, and reduced operating costs.

All ropes (synthetic, high modulus and wire ropes) should be inspected before and after an operation. This guideline ensures maximum safety for both a ship’s personnel and equipment. Even though it’s difficult to determine the exact service life span of ropes, there is a way to have a more precise estimation about their efficient lifecycle. Calculating the exact time ropes have been in use (e.g mooring time, mooring conditions, weather and tidal conditions) is the answer. All in all, rope inspections should occur at least once a year.

Inspecting wire ropes in particular, comes with great responsibility. Inspection results should be recorded, and any defects noticed have to be reported and addressed properly. Some defects can be repaired, while in some cases replacing a wire rope is inevitable.

Periodical inspections ofvessel deck equipment is also crucial for maintaining the good condition of wire ropes. The condition of the drum, chocks, bitts, rollers, sheaves, cable clamps and other end fittings, affect the rope’s performance, threads and cords. Make sure to mark these parts during your overall inspection.

In order to help marine officers and staff conduct successful wire rope inspections – and keep an up-to-date record of them – we have created an inspection solution that helps in maintaining and monitoring a ship’s ropes and deck equipment.

When calculating mass using F = Minimum Breaking Force, according to the wire rope’s diameter, you can determine the Minimum Breaking Massand therefore the wire’s max strength. When calculating mass using F = Safe Load according to the wire rope’s diameter, you can determine the Safe Load Mass,which is the advised load for this rope diameter.

The strands of a wire rope absorb the majority of the tensile force applied on the rope. Their design and manufacturing standards affect the level of fatigue resistance and resistance to abrasion. An easy way to understand which rope design is suitable for each purpose, is the wire rope classification.

Wire ropes are classified according to the number of strands in each construction and the number of wires in each strand. For example, a classification of 6X19 means that a wire rope of this type always has six strands, but its wires could be 15-26 per strand. This is because 19 is not the exact number of wires, but the classification of a wire number range.

Visual inspections are a common and fast way to assess wire rope condition. Both the standard and rotation resistant wire rope inspectionprocesscomply with the same four steps of examination. A ship’s crew can perform them as follows:

Steel wire rope distortion is obvious in most cases and can easily be identified by the inspector or the ship‘s crew. It usually occurs if load is suddenly applied or abruptly released (shock loading), or even if swift torque is forcefully induced.

Although not all of these deformations make the rope absolutely dangerous to use, they all may cause ropes to wear unevenly in time. This means inspections should take place more often, and distorted ropes should be handled with caution.

The rag and visual inspection is a good method for regular inspection intervals. The inspector pulls a rag along the rope trying to find broken wire cords. If the rug gets snagged by the rope, the inspector has to stop and assess the wire rope’s condition. Extreme caution should be exercised during the visual inspection, and under no circumstances should this method be the only one used to inspect wire ropes.

Tip: When you encounter a protruding wire end, bend it back and forth manually, until it separates from the wire. This will protect neighboring wires from wearing out.

Diameter reduction is a critical factor in steel wire rope wear and if not properly taken care of, it can result in rope breakage. Excessive abrasion, loss of core mass, corrosion or inner wire failure are all factors that contribute to diameter reduction.

To get an accurate measurement of the rope’s diameter, measure the rope at three different points at least 5 feet apart. Take the average of these three measurements to determine the true diameter.

Any measurements showing a reduction of ⅓ or more, indicate that a replacement should follow without delay. A diameter reduction of less than 1/3 still requires attention, and the inspector or the ship’s crew should be on guard in the next scheduled wire rope inspection.

Failure from abrasion or corrosion is a result of deficient deck equipment inspection or insufficient wire rope lubrication respectively. Internal corrosive damage is more difficult to identify than any other types of degradation. In most cases, the damage has progressed more than the external signs suggest.

Wire rope storage plays a significant role in the rope’s operation life.Wire rope corrosion and pitting can be avoided if ropes are safely stored in a clean, cool, dry and well-ventilated place. Steel wire ropes should not by any means rest on the floor, and should be protected from water, dust or any chemical fumes. Long term storage requires periodic greasing, turning the reel upside down for preventing grease dripping and possibly re-winding to another reel with larger inner tube diameter.

Wire ropes should be maintained with periodical lubrication. In order to prevent internal corrosion, a pressure lubricator is suggested to be used. In this case, a small amount of grease is used to lubricate the rope internally, while the deck stays grease-clean. Pressure lubricators clean the rope before they grease it so that the new grease enters a clean rope. The type of grease used is very important for maximum protection and greasing efficiency.

Steel wire ropes exposed to dirt, grime and other contaminants, have to be cleaned with a wire brush and petroleum (unless a pressure lubricator is used). Optimal cleaning of wire ropes can extend their service life and guarantee safe operations.

The reeling process is of high importance for the longevity of wire ropes. To protect them from being damaged, it is important that the surface of the drum is clean, smooth and dry. Improper reeling may cause wire-rope strands to spread or get flattened, when in contact with one another, as successive layers are being spooled and upper layers apply pressure on the lower ones.

Katradis S.A. offers a wide range of top quality wire ropes for shipping (mooring and hoisting operations), fishing and construction purposes. Our wire ropes have greater resistance to fatigue, and they distribute tension force equally among the rope strands. They are less likely to kink, providing higher staff safety and assuring operation success.

In 1998, a crane load line broke while lifting the south topside module of the Petronius platform, dropping the module into the Gulf of Mexico. The cost was estimated to be around 116 million US dollars. Since 1999 more than 60 people have been killed as a result of wire ropes breaking and more than 65 associated injuries.

Not many people appreciate that there are literally thousands of wire rope designs, most of which can be put into a specific category. According to BS ISO 4309 2010 there are currently more than 25 categories of crane wire rope, each with differing characteristics and also different discard criteria. Deterioration can be measured, counted or calculated and the wire rope eventually taken out of service based on sophisticated discard criteria published in chosen standards, codes of practice or users handbooks.

Unfortunately there is no simple answer to either of these questions. All wire ropes will eventually break due to corrosion, wear or fatigue even if they are maintained and used properly. Unpredictable wire rope failures will inevitably occur, quite often when you least expect it if the discard criteria is ignored, or those using the equipment are ignorant of it.

James Dawes of Topeka, Illinois, was killed in 2008 after being struck by the boom of a Link-Belt crane; the accident was caused by the boom hoist wire rope breaking. The crane rope had been inspected, but a report said that the inspector failed to reject the rope showing a high number of visible wire breaks. Premature or unexpected wire rope failures can also be attributed to poor manufacture, incorrect handling and storage, poor installation technique, poor selection or fitting of its termination, infrequent or inadequate inspection and poor maintenance. Of course there is always the possibility that mechanical damage can occur and this is usually attributed to human error.

It is necessary, particularly during offshore operations that frequent inspections are carried out over the whole length of the working part of all steel wire ropes. The frequency of inspections should be based on the severity of use and risk assessment and particular attention should be paid to the critical areas of the wire rope; areas that are frequently running over sheaves, compensating sheaves and the rope termination to name a few.

Figure 1. An offshore lift taking place; this one was successful but the ill-fated southtopside module of the Petronius platform remains at the bottom of the Mexican Gulf.

If a wire rope has not been subjected to an abnormal environmental condition such as excessive heat, chemical attack or any corrosive solution and it has not been the victim of any form of mechanical damage, then trained operatives and inspectors can reasonably predict the length of time the steel wire rope is likely to last. That prediction, of course, will be dependent on the knowledge and experience of those making it coupled with known facts about the rope, its current condition and the application it is running on. The Inspector should be aware of the previous rope’s history, capacities of loads and the reeving systems employed together with the frequency of use etc.

Various standards and codes of practice have been written by recognized bodies and institutes based on the experience of experts or representatives of corporate organizations who have a vested interest. These standards do offer guidance on when a wire rope should be removed from service based on wear, abrasion and fatigue amongst others things, but none of these standards have any legal status except when they are called up by contract. Indeed they can all be supported or overturned in a court of law by an expert.

The users handbook, or more importantly the safe use instructions do have legal status. In many parts of the world these days, suppliers of cranes or any machinery for that matter, issue safe use instructions with new equipment. Modern applications employ modern wire rope and, in some cases, sheaves and pulleys that are made with materials other than steel. Original equipment manufacturers of such applications may impose discard criteria for the wire rope that is stricter than those in chosen standards. By law the user must follow manufacturers’ instructions.

Wire ropes will deteriorate much more quickly if they go dry and are allowed to remain in that condition. Tests have proven that a dry rope will lose up to 60 % of its expected life if it is not re-lubricated. There are differing schools of thought as to how wire rope should be lubricated. Some believe that a thin lubricant should be applied using a paintbrush. It is thought that this method allows the lubricant to penetrate. Experience has proven however, that thin penetrative lubricants will easily drain away or fly off in hot climates.

Another school of thought, and the one I stand on, is that grease should be pressure lubricated into the rope. This method, if applied properly, will ensure that the grease penetrates the rope pushing out the old lubricant with it and any possible corrosive agents such as salt water and sand. Any lubricant that is used must be compatible with the type that was applied previously and it is a good idea to consider the environment as well.

In any event, wire ropes usually announce that they are about to break. A series of individual wire breaks can be heard. These are likely to go on over several seconds and continuing for up to ten minutes before ultimate failure. Therefore, if operatives understand the warning signals, expensive incidents could be avoided.

Figure 2 shows two pieces of the same rope, the bottom portion quite clearly shows a progression of wire breaks. The operator was able to put the load down before disaster struck. The root cause of this fault was core deterioration brought about by internal corrosion.

To answer the other question on accountability, the list is extensive. Usually the first suspect is the wire rope manufacturer and that may be where the problem lies, but very often that is not the case. What if you were supplied the wrong rope for the application? Maybe you ordered the wrong rope or your buyer bought it from a cheap unapproved manufacturing source.

Perhaps your supplier is responsible, maybe he provided you with a rope that was produced to the wrong specifications. Would you know the difference? Perhaps you were sold a rope that had been stored in the suppliers or manufactures stock for a number of years and, whilst it was there, it hadn’t been properly maintained. Maybe the rope had been badly handled or installed incorrectly. The list of possibilities is endless.

In 1999 a ropeway in the French Alps snapped causing 21 deaths. In 2003, a ropeway wire rope snapped and 7 people died and a further 42 were injured. In 2007 a crane wire rope snapped at New Delhi’s metro, the entire structure tumbled down crushing workers underneath, six people were killed and 13 more were injured. In 2009 26 people were killed and 5 people were injured when a rope failed in a mine and a further 6 people were injured when a lift rope broke inside London’s Tower Bridge.

If you find yourself in the unfortunate situation after the unthinkable premature failure of a wire rope, then you might like to know that there are independent analytical services capable of determining probable cause. One of these is Doncaster Analytical Services Ltd (DAS), they have an independent metallurgical laboratory providing factual analysis and testing of wire rope for any reason (contact Mr Shui Lee, Technical Director, Tel +44(0)1302 556063, email: shui.lee@doncasteranalyticalservices. com).

Operational safety depends not only on your equipment, but also on the awareness, skill and performance of the people who manage and use it. It is often difficult to quantify the cost benefits of training the right people but very easy to count the cost of a disaster.

You do not need a wire rope to fail in order to learn. Careful analysis of discarded ropes can also give you valuable information about your application, the way it operates, and the rope you have been using.

Based on this information, a trained, skilled and experienced inspector will be able to advise on a better crane or wire rope design, or to an improvement in maintenance procedures and safety.

Wire Rope is an item often found on Wire Rope Cranes. Unfortunately, though these wires are not unbreakable and can/will succumb to the pressure of constant use and may potentially snap when in use. Which is why it is important to know what to look out for in an unsafe wire rope, the Government of Canada recommends a visual inspection of the wire before each use, but full inspections should be undertaken by a trained professional periodically. This article will cover what causes wire ropes to break, what your professional inspector will do to ensure your rope is safe and what you can look out for when completing your frequent inspection to ensure the rope is safe to work with.

When you hear the term wire rope you may picture in your mind a metal and seemingly unbreakable rope, and through wire ropes, can and will stand up better than many other rope types it is unfortunately not unbreakable. Some things that can cause a wire rope to break include:

Kinks caused by improper installation of a rope, sudden release of a load or knots that were made to shorten a rope can cause the rope to become compromised

Many of these causes can be minimized by the use of proper crane design and rope maintenance procedures, most of these causes though are unavoidable and are considered to be part of a normal rope life. The two main causes that are considered unavoidable are crushing and internal and external fatigue.

Many wire ropes are subject to a lot of repetitive bending over a sheave, which causes the wire to develop cracks in its individual wires. These broken wires often develop in the sections that move over sheaves. This process will become escalated if a rope travels on and off of a grooved single layer drum, which causes this to go through a bending cycle. Tests in the past have shown that winding on a single layer drum is equal to bending over a sheave because it causes similar damage.

Fatigue breaks often develop in segments as stated before these segments are usually the part of the rope surface that comes into direct contact with a sheave or drum. Because this is caused by external elements rubbing, oftentimes these breakages are external and visible for the eye to see. Once broken wires start to appear, it creates a domino effect and quickly much more will appear. Square ends of wires are common for fatigue breaks. These breaks are considered a long-term condition and are to be considered part of the normal to the operating process.

Internal Breaks,these breaks can develop over time-based upon the loading of the hoist. Many ropes are made of a torque-balanced multi-strand design, which comprises of two or more layers of strands. A torque balance is created in multi-strand ropes, by layering the outside and inside ropes in opposite directions. Multi-strand ropes offer much more flexibility and have a more wear-resistant profile. Though the wires in these ropes touch locally and at an angle, which causes them to be subject to both the effect of radial load, relative motion between wires and bending stresses when bent on sheaves or drums.

Nicking and fatigue patterns such as the ones discussed before occur in Independent Wire Rope Cores or IWRC ropes. IWRC ropes have outer wires of the outer strands, which have a larger diameter than the outer core strands. This helps to minimize inner strand nicking between the outer strands of the IWRC. The outer strands and the IWRC strands are approximately parallel. Often their neighbouring strands support these outer strands while the outer IWRC wires are relatively unsupported.

With these geometrical features it allows for the wire to fluctuate under tensile loads, the outer IWRC wires are continuously forced into valleys in between the outer strand wires and then released. This system results in secondary bending stresses which leads to a large number of core wires with fatigue breaks. These breaks are often close together and form in groups. This eventually leads to the IWRC breaking or completely disintegrating into short pieces of wire that lay, half a length long. This condition is often called complete rope core failure.

It is as the IWRC fails, and the outer strands lose their radial support then valley breaksform. Valley breaks occur when the outer strand wires bear against each other tangentially. This results in interstrand nicking, which restricts the movement of strands within the rope; without the freedom to move, secondary fatigue breaks occur in the outer strands, which will develop a stand tangent points. These breaks occur in the valleys between the outer strands hence why they are called valley breaks.

So to go over what we just learned, internal broken wires occur often in ropes that are operated with large diameter sheaves and high factors of safety. These breakages can occur when a reeving system incorporates sheaves lined with plastic or all plastic sheaves; these sheave units offer more elastic support than their steel counterparts. Which causes the pressure between outer wires and sheave grooves to be reduced to the point where the first wire breaks will occur internally.

If a section of a rope travels on and off of a grooved multi-layer drum, then it goes through what is called a bending cycle. The bending cycle occurs by a section of rope spooling in the first layer and is bent around the smooth drum surface, but when the second layer rolls around the rope section in the first layer will be spooled over. This causes the first layer to become compressed and damaged on the upper side by the second rope layer. With continued spooling the rope layers in the second and higher layers will, in turn, be damaged on both sides during contact with their neighbouring rope layers. This damage is caused both by the compression of the rope and by the rope laying on a rough surface.

Accelerated wear occurs where the point of the rope is squeezed between the drum flange and the previous layer. Often times the slap of rope at the crossover points causes peening, martensitic embrittlement and/or wire plucking, further associated rope damage is caused when the rope crosses over from layer to layer on a drum.

Also, if the lower wire rope areas where not spooled under sufficiently high tension the lower wraps can become displaced by the additional rope sections which would allow for these new rope sections to slide down in between them, which will lead to severe rope damage.

Many regulators have decided that the Statutory Life Policy be overly wasteful and they tend to use the Retirement for Clause Policy. A wire rope deteriorates slowly over its entire service, but to be aware of the state of deterioration, a wire rope must be periodically inspected. Moderate deterioration is normally present, and low levels of deterioration do not justify retirement. Which is why you have wire rope inspections to monitor the normal process of deterioration. This ensures that the rope can be retired before it can become dangerous. Besides, these inspections can detect unexpected damage or corrosion on the wire rope which will allow you to take corrective actions to ensure the longevity of the wire rope.

This system is useful for detecting external rope deterioration. To use this approach, the inspector will lightly grab the rope with a rag. The inspector then glides the cloth over the rope. Often times external broken wires will porcupine (stick up). When the rope moves along the wire it will be snagged on the broken wire. The inspectorwill then stops dragging the cloth along the wire and visually inspects the condition of the wire.

Frequently broken wires often do no porcupine, which is why a different test procedure must be utilized. This test involves moving along the rope two or three feet at a time and visually examining the rope. This method though can become tiresome because oftentimes the rope is covered in grease and many internal and external defects will avoid detection through this method.

Another method involves measuring the wire ropes diameter. This involves comparing the diameter of the current rope to the original rope’s diameter. Changes in the diameter of the rope indicate external and/or internal rope damage. This method is not perfect because many different wire breakages damages do not change the diameter of the rope.

You can also check for several visible signs of distributed losses of the metallic cross-sectional area. This is often caused by corrosion, abrasion and wear. To internally check for damage, you can insert a marlinspike under two strands and rotate it to lift the strands and open the rope.

Visual inspections are often not well suited for the detection of internal rope damage. This means that they have limited value as the only means of wire rope inspection. Though visual inspections do not require special machines. When completed by a knowledgeable and experienced rope examiner through visual inspections can be valuable tools for evaluating rope degeneration.

Electromagnetic Inspections or EM gives a detailed insight into the exact condition of a rope. EM is a very reliable inspection method and is a universally accepted method for inspecting wire ropes for mining, ski lifts and other similar industries. There are two distinct EM inspection methods, which have been developed to classify defects called Localized-Flaw (LF Inspection) and Loss-of-Metallic-Area Inspection (LMA Inspection type)

LF Inspection is similar to the rag-and-visual method. This inspection method is suited primarily for finding localized flaws, such as broken wires. Which is why small hand-held LF instruments are called electronic rags.

Electromagnetic and visual wire rope inspection methods are like peanut butter and jelly or cookies and milk they are the perfect combination, and both are essential for safe rope operation. Which is why both methods are often used to ensure maximum safety.

A program that involves periodic inspections is extremely effective. To establish baseline data for future inspections, a wire rope inspection program should begin with an initial inspection after a break-in period. Then the inspections should follow at scheduled intervals, with documentation of the ropes deterioration over its entire service life.

For multi-strand ropes often times visual inspections are ineffective which is why statutory life policy for a ropes retirement is often adopted. This means that these ropes are often discarded long before they should be meaning millions of dollars’ worth of perfectly good wire ropes are being thrown away annually.

Some people have suggested that non-rotating ropes should not be used if cranes use a single layer winding on a drum. Following this line of thought, this would mean multi-strand ropes should be used only when winding on multi-layer drums. This would cause wires to break the surface faster than internal wire damage can occur, these non-rotating wire ropes will be replaced long before internal fatigue can set in.

When internal broken wires are the problem electromagnetic rope testing can be the solution. Though there are some factors one needs to take into account such as certain regulations require rope retirement when a certain number of broken wires per unit of rope length exceed a set limit. This discard number that is specified in retirement standards refers solely to external wire breaks. This means the condition of a wire rope with internal breaks is therefore left up to the inspector.

Though you also need to take into account detailed detection and quantitative characterization of internal broken wires in ropes with many breaks and cluster breaks could be a problem. These difficulties are caused by the fact that electromagnetic wire rope can be influenced by several parameters such as:

Clusters of broken wires can cause an additional problem because the relative position of broken wires concerning each other within the rope is not known

Broken wires with zero or tight gap widths are not detectable by electromagnetic inspection because they do not have a sufficient magnetic leakage flux.

When you consider all of this you can quickly realize that you can only estimate the number of broken wires that have formed on a wire rope. You can use the LF trace for the detection of broken wires, though unfortunately it is not quantitative so it cannot be used to estimate the number of broken wires. Though it is good to note that if any internal broken wires are present an LMA trace will show rapid relatively small variations of a cross-section.

An electromagnetic inspection will help to enhance the accuracy and reliability of the inspection, by combining visual and EM methods they will be able to detect deterioration at the earliest stages. The inspections can be then used as an effective preventive maintenance tool. For example, the inspector early on detects corrosion, and you immediately apply the corrective action of improving the lubrication of the wire rope.

Wire ropes should be inspected by a certified inspector when installing it, and periodically throughout its life cycle. A wire rope should go through a quick, but thorough inspection every day that you use it at the beginning and end of each shift and you should keep records of all inspections. Ensure that your certified wire rope inspector uses a combination of visual inspection methods and electromagnetic inspection methods because this will ensure the optimum safety and longevity of the rope. This is especially true for ropes that are more likely to develop internal broken wires, and inspections completed by a certified inspector is the best way of having a preventive maintenance program and extending the life of your wire rope.

Queensland Division of Workplace Health and Safety, “Non-rotating hoist wire ropes, multi fall configurations, Health and Safety Alert,” http://www.whs.qld.gov.au/alerts/97-i-5.pdf

Verreet, R. “Wire rope damage due to bending fatigue and drum crushing,” O.I.P.E.E.C.(International Organization for the Study of the Endurance of Wire Rope) Bulletin 85, June 2003, Reading (UK), ODN 0738, pp. 27-46.

Even though wire ropes are strong and reliable does not mean they are unbreakable. They can break or damage due to constant pressure or overuse. When using wire ropes you want to make sure to check them daily for damage and wear.

You can avoid the above problems by practicing proper rope maintenance procedures. On the other hand, some issues cannot be avoided so frequent inspections and checks should be done to ensure the wire rope is safe for use.

If you are worried about the conditions of your wire rope, you can implement a statutory life policy. This states that your ropes are to be retired at predetermined dates. Or you can do a retirement clause – which will allow you to use cables until they have deteriorated beyond a certain point.

Don’t wait until your wire ropes are damaged and broken, keep up with the health of your ropes! If you think you’re due for new wire ropes or an inspection, call the experts atSilver State Wire Rope and Rigging! We have a reputation for our high-quality, well-informed solutions, efficiency, and professionalism.Call usfor all your wire rope needs!

Wire rope is a complex mechanical device that has many moving parts all working in tandem to help support and move an object or load. In the lifting and rigging industries, wire rope is attached to a crane or hoist and fitted with swivels, shackles or hooks to attach to a load and move it in a controlled matter. It can also be used to lift and lower elevators, or as a means of support for suspension bridges or towers.

Wire rope is a preferred lifting device for many reasons. Its unique design consists of multiple steel wires that form individual strands laid in a helical pattern around a core. This structure provides strength, flexibility, and the ability to handle bending stresses. Different configurations of the material, wire, and strand structure will provide different benefits for the specific lifting application, including:Strength

However, selecting the proper wire rope for your lifting application requires some careful thought. Our goal is to help you understand the components of a wire rope, the construction of wire rope, and the different types of wire rope and what they might be used for. This will allow you to select the best performing and longest-lasting wire rope for the job at hand.

From childhood, many of us have been conditioned to think of a machine as some device with gears, shafts, belts, cams, and assorted whirring parts. Yet, by the rules of physics, an ordinary pry bar is a simple machine, even though it has only one part.

A wire rope is, in reality, a very complicated machine. A typical 6 x 25 rope has 150 wires in its outer strands, all of which move independently and together in a very complicated pattern around the core as the rope bends. Clearances between wires and strands are balanced when a rope is designed so that proper bearing clearances will exist to permit internal movement and adjustment of wires and strands when the rope has to bend. These clearances will vary as bending occurs, but are of the same range as the clearances found in automobile engine bearings.

Understanding and accepting the “machine idea” gives a rope user a greater respect for rope, and enables them to obtain better performance and longer useful life from rope applications. Anyone who uses a rope can use it more efficiently and effectively when they fully understand the machine concept.

Wires are the smallest component of wire rope and they make up the individual strands in the rope. Wires can be made from a variety of metal materials including steel, iron, stainless steel, monel, and bronze. The wires can be manufactured in a variety of grades that relate to the strength, resistance to wear, fatigue resistance, corrosion resistance, and curve of the wire rope.

Strands of wire rope consist of two or more wires arranged and twisted in a specific arrangement. The individual strands are then laid in a helical pattern around the core of the rope.

The core of a wire rope runs through the center of the rope and supports the strands and helps to maintain their relative position under loading and bending stresses. Cores can be made from a number of different materials including natural or synthetic fibers and steel.

Lubrication is applied during the manufacturing process and penetrates all the way to the core. Wire rope lubrication has two primary benefits:Reduces friction as the individual wires and strands move over each other

The number of layers of wires, the number of wires per layer, and the size of the wires per layer all affect the strand pattern type. Wire rope can be constructed using one of the following patterns, or can be constructed using two or more of the patterns below.Single Layer – The most common example is a 7 wire strand with a single-wire center and six wires of the same diameter around it.

Filler Wire – Two layers of uniform-size wire around a center with the inner layer having half the number of wires as the outer layer. Small filler wires, equal to the number in the inner layer, are laid in valleys of the inner wire.

Seale – Two layers of wires around a center with the same number of wires in each layer. All wires in each layer are the same diameter. The large outer wires rest in the valleys between the smaller inner wires.

Warrington – Two layers of wires around a center with one diameter of wire in the inner layer, and two diameters of wire alternating large and small in the outer later. The larger outer-layer wires rest in the valleys, and the smaller ones on the crowns of the inner layer.

On a preformed wire rope, the strands and wires are formed during the manufacturing process to the helical shape that they will take in a finished wire rope.

Preformed rope can be advantageous in certain applications where it needs to spool more uniformly on a drum, needs greater flexibility, or requires more fatigue-resistance when bending.

Direction and type of lay refer to the way the wires are laid to form a strand (either right or left) and how the strands are laid around the core (regular lay, lang lay, or alternate lay).Regular Lay – The wires line up with the axis of the rope. The direction of the wire lay in the strand is opposite to the direction of the strand lay. Regular lay ropes are more resistant to crushing forces, are more naturally rotation-resistant, and also spool better in a drum than lang lay ropes.

Lang Lay– The wires form an angle with the axis of the rope. The wire lay and strand lay around the core in the same direction. Lang Lay ropes have a greater fatigue-resistance and are more resistant to abrasion.

A fiber core can be made of natural or synthetic polypropylene fibers. Fiber cores offer greater elasticity than a steel core but are more susceptible to crushing and not recommended for high heat environments.

A steel core can be an independent wire rope or an individual strand. Steel cores are best suited for applications where a fiber core may not provide adequate support, or in an operating environment where temperatures could exceed 180° F.

The classifications of wire rope provide the total number of strands, as well as a nominal or exact number of wires in each strand. These are general classifications and may or may not reflect the actual construction of the strands. However, all wire ropes of the same size and wire grade in each classification will have the SAME strength and weight ratings and usually the same pricing.

Besides the general classifications of wire rope, there are other types of wire rope that are special construction and designed for special lifting applications.

Some types of wire rope, especially lang lay wire rope, are more susceptible to rotation when under load. Rotation resistant wire rope is designed to resist twisting, spinning, or rotating and can be used in a single line or multi-part system.

Special care must be taken when handling, unreeling, and installing rotation resistant wire rope. Improper handling or spooling can introduce twist into the rope which can cause uncontrolled rotation.

Compacted strand wire rope is manufactured using strands that have been compacted, reducing the outer diameter of the entire strand, by means of passing through a die or rollers. This process occurs prior to closing of the rope.

This process flattens the surface of the outer wires in the strand, but also increases the density of the strand. This results in a smoother outer surface and increases the strength compared to comparable round wire rope (comparing same diameter and classification), while also helping to extend the surface life due to increased wear resistance.

A swaged wire rope differs from a compacted strand wire rope, in that a swaged wire rope’s diameter is compacted, or reduced, by a rotary swager machine after the wire rope has been closed. A swaged wire rope can be manufactured using round or compacted strands.

The advantages of a swaged wire rope are that they are more resistant to wear, have better crushing resistance, and high strength compared to a round strand wire rope of equal diameter and classification. However, a swaged wire rope may have less bending fatigue resistance.

A plastic coating can be applied to the exterior surface of a wire rope to provide protection against abrasion, wear, and other environmental factors that may cause corrosion. However, because you can’t see the individual strands and wires underneath the plastic coating, they can be difficult to inspect.

Plastic filled wire ropes are impregnated with a matrix of plastic where the internal spaces between the strands and wires are filled. Plastic filling helps to improve bending fatigue by reducing the wear internally and externally. Plastic filled wire ropes are used for demanding lifting applications.

This type of wire rope uses an Independent Wire Rope Core (IWRC) that is either filled with plastic or coated in plastic to reduce internal wear and increase bending fatigue life.

Remember, wire rope is a complex piece of mechanical machinery. There are a number of different specifications and properties that can affect the performance and service life of wire rope. Consider the following when specifying the best type of wire rope for your lifting application:Strength

When you select a piece of rope that is resistant to one property, you will most likely have a trade-off that affects another property. For example, a fiber core rope will be more flexible, but may have less crushing resistance. A rope with larger diameter wires will be more abrasion resistant, but will offer less fatigue resistance.

At Mazzella Companies, we offer all different kinds of wire rope from all of the leading manufacturers. We sell the highest-quality domestic and non-domestic rigging products because product quality and operating safety go hand-in-hand. We have one of the largest and most complete inventories of both domestic and non-domestic rigging and lifting products to suit your lifting needs.

If you’re looking for a standard or custom specified wire rope for your lifting project, contact a Lifting Specialist at a Mazzella Companies location near you.

We stock well over 2,000,000 feet of wire rope in our various locations … ready for immediate delivery! We provide wire rope assemblies, and manufacture bridge cables, crane cables, steel mill cables, and thousands of OEM assemblies.

Wire rope is a collection of metal strands that have been twisted and wound to form the shape of a helix with the purpose of supporting and lifting heavy loads and performing tasks that are too rigorous for standard wire. On shipping docks, rigging, and load bearing equipment, wire rope is attached to swivels, shackles, or hooks to lift a load in a controlled, even, and efficient manner.

The uses for wire rope include adding support to suspension bridges, lifting elevators, and serving as additional reinforcement for towers. The design of wire rope, with its multiple strands wrapped around a stable core, provides strength, flexibility, and ease of handling for applications that have bending stress.

Individual designs of wire rope involve different materials, wire, and strand configurations as a means for supporting and assisting in the completion of lifting or supportive applications.

The term wire rope encompasses a wide range of mechanical tools that are made to perform heavy and extreme lifting jobs. Wire rope is a complicated and complex tool with multiple moving parts capable of moving in unison. A 6 by 25 wire rope has 150 outer strands that move as one in an intricate pattern supported by a flexible core.

An essential part of the design of wire rope is the required clearance between the strands to give each stand the freedom to move and adjust when the rope bends. It is this unique feature that differentiates wire rope from solid wire and other forms of cable.

The basic element of wire rope is wire that is used to configure, shape, and form the rope. Typically, steel, stainless steel, and galvanized wires are the first choice with aluminum, nickel alloy, bronze, copper, and titanium being second possibilities. The choice of wire is dependent on the type of work the wire is going to be used to perform with strength, flexibility, and abrasion resistance being the major determining factors.

Stainless steel wire rope has all of the basic qualities of galvanized and general wire rope with the added benefits of corrosion and rust resistance; this makes it the ideal choice for harsh and stressful conditions.

Steel wire rope is classified as general purpose wire rope and comes in a wide variety of sizes, diameters, and strengths. It is the most common type of wire rope and is used for several industrial, manufacturing, and construction applications.

Before going further into the discussion of how wire rope is made, it is important to understand the numbers used to describe each type. All wire ropes have a core around which wires are wound. The various styles of cores vary according to the construction and design of the requirements of the wire rope that is being produced.

Wire rope is classified by the number of strands it has as well as the number of wires in each strand. The most common classification is a seven wire rope that has one strand in the center and six around its circumference. This type of wire rope is lightweight with a very simple construction. The majority of wire ropes are more complex and intricate with multiple intertwining strands and wires.

What must be understood about wire rope is that it has a complicated configuration. It is actually wires wrapped around wires to form bundles that are wrapped around other bundles. In the case of a seven wire wire rope, the core has bundles of wires wound around it; this can be seen in the image below.

The first step in wire rope creation is the production of wire strands where wires are wound around a single core wire. The number of wires included in the strand is dependent on the specified strength, flexibility, and size requirements of the rope. Once the strand is completed, it is straightened before being moved to wire rope construction.

Like wire ropes, strands have different patterns; patterns are the arrangements of the wires and their diameters. Though most strands have a core, there are strand patterns that have three or four wires without a core that are referred to as centerless strands. The design of each strand pattern is meant to enhance the strength of the wire rope and improve its performance.

For a multiple layer strand, the layers of wire are placed over one another in successive order. The placement of the wires on top of each other must be such that they fit smoothly and evenly.

The Warrington pattern is like the multiple layer pattern with one variation. Like the multiple layer pattern, the inner wires and the core are the same and have the same diameter. The difference is in the outer layer, which has wires of alternating sizes of large and small with larger diameter wires laying in the valleys of the inner wires.

All of the wires of a filler pattern are the same size. What makes this pattern unique is the insertion of small wires in the valleys of the inner wires to fill the gap between the inner and outer layer.

The flattened strand pattern is also known as the triangular strand, which can be triangular or oval. Three round wires form the core. The outer flattened surface has a greater sectional metallic area; this makes this pattern stronger and longer lasting.

The core of a wire rope runs through the center of the rope and can be composed of a variety of materials, which include synthetic fibers, natural fibers, a single strand, or another wire rope. The core supports the wound strands, helps maintain their position, is an effective lubricant carrier, and provides support.

Wire ropes with fiber cores are restricted to light loads and are not used in severe, harsh, or stressful conditions. Polypropylene and nylon are types of synthetic fiber cores and can be used in conditions where there is exposure to chemicals.

Cores made of wire are classified as independent wire cores. The core of a wire rope with a wire core is actually a wire rope with another wire rope serving as the core, as can be seen in the diagram below. These types of wire ropes are used where the rope will be exposed to exceptional resistance and crushing.

A strand, or wire strand core, is exactly like the rest of the strands of the wire rope with wires of the same diameter and size as the other strands.

The choice of core and creation of the strands are the simplest yet most essential parts of wire rope construction. Wire rope lays, the method used to wind the strands, is more complex and involves several choices.

Lay is a term used to describe three of the main characteristics of wire rope: direction, relationship, and linear distance. The strands can be wrapped around the core going right or left. Right or left refers to the direction of the strands wrapped around the core and the wires within the strands. The linear distance is how far a strand moves when it is making a revolution around the core.

In a regular lay, the wires and strands spiral in opposite directions. With a right hand regular lay, the wires spiral to the left and the strands to the right. In the left hand regular lay, the wires spiral to the right and the strands to the left. This type of lay is easy to handle but wears out quickly because the crown wires are in contact with the bearing surface.

In the Lang, or Albert, lay, the wires and strands spiral in the same direction with right hand lay being the most common. The wires in a Lang lay appear to run parallel to the center line of the rope. The difficulty with Lang lay wire ropes is handling since they tend to kink, twist, and crush.

Wire rope is an exceptionally strong tool that has been configured and designed to withstand the stress placed upon it through rigorous and continual use. In most applications, wire rope has to endure extreme stress and strain. It is for these reasons that coatings have been developed to protect wire rope from abrasions, corrosion, UV rays, and harmful and damaging chemicals.

Three main types of coatings are used to protect wire rope: polyvinyl chloride (PVC), polypropylene, and nylon. Of the three types, PVC is the most popular.

PVC is popular because it is multifunctional, extremely flexible, and general purpose as well as low cost. It has an operating temperature between -30° F (-35° C) and 180° F (80° C) with a hardness of 90 on the durometer.

In cases where there are severe and hazardous working conditions, polypropylene is the recommended choice since it is capable of protecting wire rope against corrosion and chemical leaching. Additionally, it is resistant to impact damage and abrasion. Polypropylene is a tough, rigid, and crystalline thermoplastic that is made from a propene monomer and is resilient as well as inexpensive.

Nylon is exceptionally abrasion resistant, which makes it ideal for use in cold environments. It is not as flexible as PVC but has excellent protection against corrosion and impact. It has excellent chemical resistance at temperatures between -65° F (-54° C) and 230° F (110° C) and is available in a wide assortment of colors, or it can be transparent.

Braided wires are electrical conductors made up of small wires that are braided together to form a round tubular braid. The braiding and configuration of braided wire makes them very sturdy such that they do not break when flexed or bent. Braided wires are widely used as conductors, are commonly made from copper due to copper"s exceptional conductivity, and can be bare or coated depending on the application.

Braided wire can be round and tubular or flat. Round tubular braids fit in most spaces where flat braided wire will not. Flat braided wire begins as round braided wire which is flattened on a capstan. They are exceptionally strong and designed for medical and aircraft applications.

Metals used to make wire rope are various grades of stainless steel, bright steel, and galvanized steel. Though the majority of wire rope manufacturers use these three metals, other metals such as copper, aluminum, bronze, and monel are also used on a limited basis.

The most important aspect of wire rope is the wire and the metal from which it is made. The strength and resilience of wire rope is highly dependent on the quality of metal used to make it, and these are essential factors to be considered when purchasing it.

Bright steel wire does not have a coating and is rotation resistant, (designed to not rotate when lifting a load). It is drawn from hot rolled rods that are put through a die to match its specific dimensional tolerances, mechanical properties, and finish. Bright wire is used as a single line in conditions that require a rope that will resist cabling.

Galvanized steel has a zinc coating for corrosion resistance and has the same strength and durability as bright steel. Environmental conditions determine the use of galvanized steel. In mildly severe and slightly harsh conditions, galvanized steel wire is an economical replacement for stainless steel.

In the manufacturing process, galvanized wire goes through the process of galvanization, a method of coating steel wire with a protective and rust resistant metal. Galvanized wire is exceptionally strong, rust resistant, and flexible enough to meet the needs of a variety of applications.

Stainless steel does not have the same strength and endurance as bright steel or galvanized steel but has the many benefits commonly associated with stainless steel, such as resistance to stains, wear, rust, and corrosion. More expensive than the other two metals, stainless steel has the added benefit of lasting longer and providing exceptional performance.

Wire rope made from copper is mostly used for electrical applications due to its exceptional electrical characteristics. The benefits of copper wire rope are its durability, flexibility, and resilience compared to standard copper wire. The strength of copper wire rope is seen in its use in applications where there are vibrations and shaking.

The wire rope lubrication process begins during its fabrication and continues during its use. Lubrication of wire rope is designed to lower the amount of friction it endures and provide corrosion protection. Continued lubrication increases the lifespan of wire rope by preventing it from drying up, rusting, and breaking.

The types of lubricants for wire rope are penetrating or coating with coatings covering and sealing the outside of the rope. Penetrating lubricants go deep into the rope and seep into the core where they evaporate to form a thick coating or film.

The application of the lubricant is dependent on the type of core. Fiber cores absorb the lubricant and serve as a reservoir that retains the lubricant for an extended period of time. With metal cores, the lubricant is applied as the wire is twisted into strands to give complete saturation and coverage of the wires.

Petrolatum compounds are translucent and provide excellent corrosion and water resistance. They tend to drip off at high temperatures but keep their consistency in cold conditions. Petrolatum is a mixture of hydrocarbons from the distillation of petroleum that belong to the methane family of hydrocarbons. It can be used in semi-solid or liquid form and forms a jelly in its semi-solid form.

Asphaltic compounds are a mineral based oil combined with bitumen to create a tacky, high viscosity lubricant with an undiluted viscosity. As a lubricant, asphaltic compounds create an oil film that separates the mating surfaces and are applied as a spray. Once applied, the meshing of surfaces causes the solvent to flash; this leaves a viscous coating of lubricant.

There are several types of greases that are used as wire rope lubricating agents and are made up of oil, a thickener, and additives. The essential components are the base oil and additives, which influence the behavior of the grease. The thickener holds the base oil and additives together. The amount of base oil in a grease is between 70% and 95% with an additive of 10%.

The additive in grease enhances the positive properties of the oil and suppresses the negative properties. Common additives are oxidation and rust inhibitors as well as pressure, wear, and friction reducing agents.

Of the many choices for lubricants, vegetable oil is the easiest to use and penetrates the deepest. The design of the additives for vegetable oils gives them the necessary qualities required to penetrate deep into a wire rope. The exceptional penetration provides protection against wear and corrosion. Since vegetable oil is a fluid, it helps in washing the wire rope to remove external abrasive contaminants.

Wire rope is widely used in machines, structures, and varied lifting applications. Its type, size, and requirements are determined by how it will be used. Regardless of its use, wire rope guarantees exceptional strength and provides high quality and excellent performance.

The lifting of heavy loads for centuries involved the use of hemp rope or chains, neither of which was a guaranteed or substantial method. Early in the 18th Century, between 1824 and 1838, Wilhelm Albert, a German mining engineer, combined the twisting of hemp and strength of chains to create today‘s wire rope.

The most common use of wire rope is as a part of a crane hoist wherein it is attached to the hook of the hoist and wrapped around a grooved drum. The tensile strength and durability of wire rope makes an ideal tool for lifting and keeping loads secure. Though it is used in several industries, it is very popular for production environments wherein materials need to be lifted quickly and efficiently.

In addition to its many lifting applications, the strength and stability of wire rope is useful in other applications, especially in the aerospace industry. Pedals, levers, and connectors in the cockpit of an aircraft are connected with wire rope. The wires provide for the passage of power between systems and mechanisms; this allows control of the aircraft. Wire rope is used to control propeller pitch, cowl flaps, and the throttle. It also assists in lowering and minimizing vibrations.

Tires are reinforced with wire rope to increase their durability and strength. All automotive production environments make use of wire ropes for supplying materials, moving heaving loads, and positioning equipment. Wire rope can be found in the production of steering wheels, cables, exhausts, springs, sunroofs, doors, and seating components.

As surprising as it may seem, the place that wire rope has the greatest use is in the home, where its strength, long life, endurance, and resilience provide guaranteed protection and performance. The main reason wire ropes are so popular for home use is cost.

Inexpensive, easy to obtain, easy to install, and easy to maintain, wire ropes provide an additional method for performing home repairs and structural support. Their excellent flexibility and sturdiness combined with their invisibility has made wire rope an ideal solution to several home maintenance issues. It is used to support staircases, fences, decks, and hang plants.

The search and production of crude oil has relied on wire ropes for centuries to lift drill bits, insert shafts, and support oil rigs on land and the water. When equipment, machinery, and tools have to be lowered into the dept