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
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 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.
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.