Steel wire ropes are widely used in various industrial applications for rigging, lifting, moving, loading heavy objects, or for other infrastructure projects. They are our preferred lifting devices due to their unique design that provides flexibility, strength, and the ability to handle crushing and bending stresses. It can be applied for multiple purposes such as cargo handling in harbors and on ships for heavy-duty lifting purposes, worker’s site protective equipment, cranes in offshore and onshore, ropeway for the transport of goods and passengers, etc. With a wide range of selections on wire rope available in the market, it is important for us to understand its classification, lay, and construction.
Wire rope has consisted of three components which are the Core, Strands, and Wires:
1. The core is at the center of the rope. It can be made by fiber material (natural or synthetic polypropylene fibers) or steel. Steel cores provide better support than fiber core, it can be used for high heat environment where the temperature exceeds 180° F. Fiber cores provide greater elasticity than steel cores, but it is easier to be crushed and not recommended to be used in a high heat environment.
2. Strands, which are a group of individual wires wrapped around the core.
3. Wires are single individual pieces of metal that drawn to a small diameter. Wires will be finished in different coatings such as zinc/galvanized coated, stainless steel, aluminum alloy coated, or unfinished steel (Bright).
Wire rope can have different types of lay and direction which refer to the way of the wires are laid to form the strand and the strands are laid around the core. The direction of the strands are wrapped or layed around the core can be classified by LEFT lay and RIGHT lay. In addition, we will introduce three types of lay between wrap direction of strands and wires:
1. Regular Lay - The direction of the strand lay is opposite to the direction of wire lay in the strand. The wires are line up with the axis of the rope. This type of lay is more resistant to rotation and crushing forces.
2. Lang Lay - The strand and wire around the cope are laid in the same direction. This type of lay direction has a greater resistance to abrasion and better fatigue-resistance.
3. Alternate Lay - The wire rope has alternating regular and lang lay strands which is mainly used for special application.
Wire rope can also be classified by its number of strands and wires. For example, A wire rope is classified by two numbers such as 6 x 25. The first digit represents the number of strands in the rope, whereas the second digit represents the number of wires in each strand, but it stands for the range of numbers and may not be the exact number of the wire in the strands.
Bright Wire, Galvanized Wire, and Stainless Steel Wire
1. Bright Wire - is referring to an untreated wire surface, without any coating such as zinc, copper, tin, etc. It has the lowest prices among these three types of wire ropes. In general, it is lubricated in order to protect it from corrosion and rust.
2. Stainless steel wire rope - Chromium is added into the steel to offer some degree of protection against corrosion and rust. However, standard stainless steel is not fully immune to these environmental factors such as weather, marine, etc. It is most commonly used in places not exposed to outdoor elements and environments. Stainless steel wire rope is available in grades 304, 305, 316. Stainless steel grade 316 can be used in marine location as it contains molybdenum which helps to increase its level of corrosion resistance to chlorides such as seawater.
3. Galvanized wire rope - A coating layer of zinc is added on the steel wire rope to provide excellent corrosion resistance. However, this type of coating will be breached over a period of time and will affect its protection to the internal steel wire. Galvanized wire rope can be exposed to outside weather, wet or humid conditions. Generally, galvanized steel wire rope is used in engineering applications such as security rope or winches. It can be applied in various places as an alternative choice to stainless steel.
Let’s do a summary on the differences between stainless steel and galvanized steel wire rope:
1. Tensile Strength- In case that stainless steel is combined with chromium when it is in the liquid molten state, this has created an additional tensile strength than galvanized wire rope.
2. Weight- Galvanized wire rope is lighter in weight.
3. Price- Stainless steel tends to have a slightly higher cost than galvanized wire rope.
4. Pressure- Stainless steel is able to withstand higher pressure and it is ideal for high altitude temperature environments.
5. Application: Stainless steel can be used in oil and gas process
Plastic impregnated wire rope
Wire rope coated with a layer of PVC, nylon, or other plastic materials. The coating is added to provide an extra level of safety and it is proven to be a versatile rope that is suitable to be used outdoor or indoor. Whenever a longer service life or cleaner environment is needed, a plastic-coated wire rope can be considered as your choice as the coating has extended its useful lifespan and protect against abrasion, corrosion, etc.
MecHero supplies a wide range of steel wire rope in Malaysia. Please do not hesitate to contact us at 011-7001 7687 or submit inquiry from our website. Our steel specialists are ready to give you a professional service.