Tag Archive : rope

steel wire rope

An Overview Of Steel Wire Ropes

Lifting operations are executed in all areas of the iron and steel plant. In such operations, we require reliable materials for the safety of the workers. Steel wire ropes are a crucial material since everything depends on its performance.

Steel wire rope is commonly called steel cable. They are constructed of several thin strands of steel wires wound into a helix. The multiple steel wires that form separate strands are laid in a helical pattern around a core. The commonly used layout is six strands. For example, the number of wires in each strand is 6 * 19, 6 * 36, 6 * 61. The structure provides flexibility, strength, and the ability to resist bending. Different applications of the material, strand, and wire structure provide different benefits.

Wires are building blocks of a steel wire rope. The strands are helically placed together around a centre, which is called a core, to form a wire rope. The design strands affect the properties, like resistance to abrasion and fatigue resistance. Selecting the proper wire rope for a lifting operation needs careful considerations.

Components Of Wire Rope

There are 3 basic components in the design of a steel wire rope. They are:

  • Wires produced from steel that forms a singular strand
  • Multi-wire strands laid in a helical pattern around a core
  • The core

Wires

They are the basic and smallest components of wire rope, and wires make up individual strands of rope. Wires are made from various metal materials such as steel, iron, and stainless steel. The wires are manufactured according to certain grades related to strength, fatigue resistance, corrosion resistance, resistance to wear, and curve of wire. Forming a strand of the correct size and characteristics needs high precision. The wire can be coated but is commonly available in an uncoated or bright finish.

Strands

Strands of a wire rope include two or more wires arranged and twisted in a specific arrangement. These individual strands are laid in a helical pattern around the core of the steel wire rope. Strands made of larger diameter wires have high resistance to abrasion, while strands of smaller diameter wires are more flexible.

Core

The crux of a steel wire rope is the prime feature. It is presented in the centre of the steel wire rope. It supports the strands in the rope to maintain their relative position under bending and loading stresses. Cores can be made from various materials, including synthetic or natural fibres and steel.

Advantages Of Steel Wire Ropes

  • Increased resistance to corrosion
  • Increase in resistance to abrasion
  • Low contact pressure
  • Higher flexibility
  • Bigger metallic area
  • Large surface area
  • Resistance to metallic damages
  • Reduced mechanical stress on rope and sheave.
  • Cost reduction because of reduced rope abrasion and increased service life at less expense

Causes Of Failure:

Some common causes of steel wire rope failure are:

Kinking- This results in rope deformation and localised wear.

Overloading- Causes accelerated wear, rope crushing, abrasion, and complete rope failure.

Whipping- Whipping a line results in squared-off broken wires.

Improper spooling- Results in crushed and distorted ropes.

steel wire rope

Characteristics Of A Good Steel Wire Rope

It is critical to evaluate the application’s different characteristics when choosing the appropriate steel wire rope and then priorities these properties. It is also crucial to be informed of the applicable rules and regulations. 

Tensile Strength

The tensile strength of a steel wire rope is determined by its size, wire tensile strength, and structure. The Randers Reb product catalogue lists the minimum guaranteed tensile strength for several rope types.

A steel wire rope should never be exposed to a load greater than 50% of its breaking strength.

Abrasion Resistance

Steel wire ropes with thick outside wires are abrasion-resistant. Lang lay ropes are more resistant to abrasion than standard lay steel wire ropes. Wires with higher tensile strength may also help to improve abrasion resistance.

Bending Fatigue Resistance

The strand’s bending fatigue resistance and flexibility increase as the number of wires increases. Lang lay steel wire ropes are more resistant to bending fatigue than standard lay steel wire ropes. 

Resistance To Corrosion

Wires that are galvanized and rustproof provide high corrosion resistance. Corrosion resistance may also be improved by lubricating with specific kinds of grease or oil. It is recommended that strands with thick outer wires be used if the steel wire rope is exposed to severe corrosive effects.

Elongation

Steel wire ropes with fewer wires, the most excellent elasticity modulus. Therefore, this steel wire rope is perfect for manropes. However, it cannot be used to run over sheaves or blocks. Thus, 6×7 or 6×19 steel wire rope, either with a steel core or with specific unique constructions, should be utilised if just a modest degree of elongation is needed while passing over sheaves.

The Standard For Rotation Resistance

Steel wire rope with a regular lay offers more resistance to rotation than steel wire rope with a lay. A steel wire rope with a steel core spins slower than one with a fibre core. Low-rotation and rotation-resistant steel wire rope is the kind of rope that offers the most resistance to rotation.

Crushing Resistance

A steel core offers more excellent strand stability than a fibre core, which is why a steel wire rope with a steel core has a lower chance of flattening. In addition, flattening/crushing resistance is higher in strands with fewer, thicker wires. 

Resistance To Vibrations

Vibrations transmit shock waves through the steel wire rope from wherever they originate, absorbed by the steel wire rope at some point. In certain instances, they cause localised destruction of the steel wire rope. This may happen, for example, when the steel wire rope meets a sheaf/block or enters the drum, as well as at the end terminals. Steel wire ropes with the highest flexibility also have the highest vibration resistance in general.

Resistance To Pulsation

Variations in the tension of a steel wire rope may decrease its life expectancy depending on the magnitude and frequency of the changes. Steel wire ropes with the highest elasticity, in general, can handle intermittent loads better. However, end terminals or fittings should be used with caution, as their pulsation resistance is just as essential as choosing the appropriate steel wire rope.